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form an aliquot part of 12, we must make an allow-
ance for it. Suppose, for instance, that the substiler
line should not be on the line of X., but between IX.
and X., we must find how much to allow for it before
commencing our reckoning. For the sake of example,
suppose the longitude should be 2h. 20min. This,
converted into degrees, will be 35°, and. using the
same formula-namely, R: sin. 14:: tan. 5: tan. dist.
-we shall have 1° 13. Having measured this distance
from the substiler line, we must compute the hour-
ares by taking it in, and instead of taking tan. 150,
tan. 30°, &c., we must take tan. 20°, tan. 35°, &c.,
adding 5° to each; but in the morning hours, by the
same process, we find we must allow 2° 28' from the
substiler line to the hour of IX., and instead of tan. 15o,
tan. 30°, &c., we must add 100, and compute by tan
25°, tan. 409, &c.; and by working them out in this
way we shall obtain all the hour-ares. In conclu-
sion, we must remember in all these kinds of dils
to place the gnomon parallel with the axis of the
world, or point to the poles, and to apply the equation
of time when we set our clocks and watches by them,
and then, like the great sun of the universe, we may
always depend upon an unerring guide to direct us to
our several duties.
T. S. H.

P.S. Your highly-instructive correspondent F.R.A.S.," whose papers it is a pleasure to peruse, recommends "Heather on Mathematical Instruments and Dialling Scales," but I venture to say that although its contents are most valuable, and its directions on dialling quite sufficient for those to whom the art is like ABC, yet it is not full enough for others, nor does it give any directions whatever for the construction of declining and reclining dials. The hourarcs may also be found by that useful rule, the sector, but with much more trouble and far less accuracy than by the method prescribed, which is nothing more than addition and subtraction. In last letter, page 15, in the diagram, for "60" read "68°;" and for the **angle A C B 309 + 909 " read "angle A C B 27° + 90°."

EXPLANATORY.

SIR-I cannot see anything in my letters entitling "FRA.S." to suppose I had him in my thoughts when I referred to what the German poet has said about "strong men." All the same, I would submit to him my doubts whether it befits a real lover of science, as he undoubtedly is, to "eschew discussion ab initio on every moot point whatever;" nor can I think that the abandonment of "a winning cause" (in itself hardly a commendable thing) would justify the course of dropping an argument when one finds one has made a

mistake.

TURRET CLOCKS.
SIR,-Several correspondents in the last number of
the MECHANIC ask for more information about the
clock I described in your pages a short time ago; I
will, with your permission, afford them it. Enclosed
is a drawing, showing how the quarter train is dis-
charged and stopped. A is the pin wheel. Three
times in the hour a pin presses down the lifting piece
B, which has two bits of steel rivetted in it. The
locking arm C has also a bit of steel, which comes
against the stop on the lifting plece, when it is allowed
to fall by the wedge of hard steel rivetted in it drop.
ping into the notch in the cam wheel D, and the detent
Finto the notch in the locking plate E. When the
end of the lifting piece is pressed by one of the pins,
the heavy end rises, and lets one of its stops slip past
the stop on the locking arm C, which moves forward
in the direction of the arrow, and comes against the
warning stop two or three minutes before the quarter
is to be struck. When the end is free of the pin, the
heavy part falls back into its former place, the cam
wheel revolves and raises the stops on the lifting
piece out of the way of the locking arm,

the usual way.

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and the num

ber of strokes is determined by the distance of the also the pin plate, and works two levers. The lifting notches in the locking plate, which, in this case, is piece B must fall quite dead, or it may fail to stop the train, and therefore the detent F must not touch the bottom of the notch. The hour-discharging I have brought no charge of either sort, however, does not work the hammer lever, and the lifting piece mechanism is the same, only then the locking plate against F.R.A.S.," for whose scientific attainments end is not pressed down, but raised by the pin in the and surprising general accuracy (when one considers the wide range of objects he treats of) I have the high-going part, I said nothing about the dial work, or the est possible respect. If I were disposed to do so, I way the pointers are drives, because it is not done in should be far more inclined to dwell on his spectrum analysis illustration than on his theory respecting There was an old thirty hour clock, which had been object glasses. The latter is a matter of opinion, the going for nearly two hundred years, and was about former a question of fact; and any one who is desi- showing the hours. About three years ago I put worn out, already in the tower; it had only one hand, rous, as I confess I am, of seeing the truth laid as machinery to it for striking the quarters. Chauge clearly as possible before people, might fairly ob-wheels were used, and I sent a description, which was ject to a statement which is opposed, I submit, to published in the ENGLISH MECHANIC. I also put the very principles on which spectroscopic analysis another hand to the clock, showing the minutes. The depends. But in praising (as was just) our contributor method was simple, but objectionable, as the minute T. A.." I was not "making a cap;" so that I need hand was next the dial, fastened on a tube. I should dwell no farther on a discussion which I also have prefer to use dial wheels in the usual way; they desired to drop." would be much more costly than change wheels, When I removed the old clock, I found the wheels none the worse for their nearly three years' work. The quarters had been striking at their regular intervals, and I had been well repaid for my labours by hearing their musical sound.

RICHARD A. PROCTOR.

on four bells, as at Westminster. It can be done very well with six bells, if they are in the key of E flat. Í should be happy to describe the machinery, together with a novel method of fixing the hammers to the bells, if it would be of interest to your readers.

THE ILLUMINATED PORTION OF THE
MOON'S DISC.

SIR, I think Mr. Beardsley is right in not accepting the explanations already given as exhaustive; for if, when the moon is only two days old, an imaginary line be drawn from its centre, and made to pass through its surface in the centre of the edge of the illuminated are and prolonged in would not cut through the sum at all, but would be almost at right angles with that luminary; but a line drawn from the centre of the moon through that part of the surface which is in the centre of the illuminated half (for we all know that one-half of the moon is always to the sun was prolonged, it would cut through the centre of the sun.

Now, sir, when the moon is about the end of the first or third quarter, one-half of the illuminated portion is turned towards the earth, the other half of the illuminated portion is turned away; therefore, in this case, the centre of the whole illuminated moon, and the centre of the illuminated edge as seen from the earth, coincide; so that in this part of its orbit the illuminated portion of the moon's dine in fairly directed to the sun, allowance being made for optical effects. W. F. SWALLOW.

BREAD-MAKING.

SIR, I cannot pass over "T. Estee's" letter with-
out a few words of comment upon it, as I certainly
think your correspondent has never tasted good
unfermented bread. We have used it for 21 years,
and scarcely ever failed in having excellent, sweet,
moist bread. As to its being injurious to the system,
I think it must be far otherwise, as I am myself an
invalid of many years' standing, and attribute my
present state of health entirely to the use of this
bread, As regards the recipe for baking powder
given by T. E.," I think the quantity of rice so
pastry with it.
large, that any one would fail to make good cakes or
Our proportions for baking powder
soda, 4 do. ; ground rice, 1 do.
are as follows-viz., tartaric acid, 3oz.; bicarbonate of
mode of operation of making our bread in the space
As I cannot give the
of a letter, I must refer "T. E." to the Famdy Friend
of 1850, vol. 2, page 176, where he will find the full
particulars.

THE AUTHOR OF THE ARTICLE ON UNFERMENTED
BREAD IN VOL. 2 OF "FAMILY FRIEND," 1ST
SERIES.

SIR,-"T. Estee" makes a vital mistake in confounding fermented with unfermented bread. The with a little water, while no amount of kneadlatter may be kneaded into a kind of raw paste ing will effect this change in the former, which, for persons, including the writer, cannot eat unfermented this reason, sits more lightly on the stomach. Many bread. Yeast acts chemically on flour, "powders "act mechanically. Buy a shilling treatise on baking of any bookseller for theory, aud when you have spoiled a few bakings aud brewings you will find out how good sweet bread is made. If you value this commodity your trouble will not be lost. Don't try to make good bread out of bad flour. Don't let rice come in contact with yeast. NEW SUBSCRIBER.

CRIMINAL LITERATURE. SIR,-A clergyman, on the 31st ultimo, wrote under the above heading thus to the Times:"Sir,-A short time ago you recorded the conviction of A correspondent asks why I use cast iron wheels CARBURETTING GAS. several vendors of immoral prints, not on the prosecution in preference to brass ones. Simply because irou SIR,-" Adolescens "asks, at p. 645, Vol. X., if he can of the Government, but of a society whose successful wheels cost only about a quarter of the price of brass fit gas burners to his 4in. condenser lanterns? and as I operations have made them insolvent. To-day you ones. No doubt the train is a coarse one, but with have done this for some years past, I am happy to record the words of Mobbe, the murderer:-I had weight enough on the barrel it will do its work well. tell him how I fitted them, as " V. W." page 659, proseen a picture of the man Baker murdering the girl in For the going part, 150lb. is hung on a 6in. diam. poses a method which I think would prove a very the hop-gardens.' Week after week the illustrated barrel; that is a great deal, but with a gravity escape- dangerous one, and I should like to know if he has records of crime are circulated over the length and ment it does not interfere with the time-keeping pro- actually used the arrangement he describes. "Adobreadth of the land. In my country parish the Illus-perty of the clock. I believe, from what I have seen lescens" will have to select very fine hole argand trated Police News has a large circulation. Its pictures of the performance of the clock-and I kept it going burners (32 will be required for such powerful lanterns represent crime in varied phases; its letter-press is in my workshop during the time the hour and quarter as he has), and they must be fitted with a conical ring explanatory; but its most damaging part is to be pasts were being done that it will not vary more than round the outside of the burner, to cause a current of found in its advertisements. And yet as the law a minute in a month from mean time, when the pen-air to impinge upon the outside of the flame, and thus stands I much question if it can touch this publica- dulum, of varnished steel, is regulated. It takes about compress the flame to a smaller diameter. I have tion. Has no M. P. time to consider first and give half a minute to wind the going part up, and by lift- found with such burners that a common straight notice next of a motion upon this subject? Surely ing up a ratchet lever, geared to the third spindle, chimney gives the best light, but he must fit fine wire crime in England should have its share of considera- from below, a maintaining power is kept up. The gauze under the centre of the burners to obtain a pertion with crime in Ireland, and it strikes me that it is weight on the barrel of the hour part is 350lb., and fectly steady flame. Ordinary coal-gas will not give somewhat important to protect innocence as we lifts a hammer high enough to bring out the sound a sufficiently powerful or white light for lanterns, and spread education; but it unhappily appears that well from the tenor bell, weighing, I should say, 16 or must be carburetted, as described by “ V. W.; " but I while we are squabbling as to whether religion may 17 cwt. The quarter bells in proportion. I obtained advise" Adolescens" not to attempt to make a vessel be taught in our schools, we are permitting vice to be the change wheels of J. Buck, Newgate-street, but inside the lanterns, as, unless he is an experienced taught everywhere." Mr. Lloyd, 135, Steelhouse-lane, Birmingham, has hand, he will be very likely to have a dangerous explosent me his supplementary wheel list, and it appears sisu, as the heat of the lanterns in use would soon he can supply many other numbers of teeth besides cause the naphtha in the tin vessel to volatilise too those I mentioned, amongst others, the 130 tooth wheel rapidly and burst the vessel, or make a smoky flame I wanted, from excess of hydrogen vapour. A simpler and cheaper plan is to use a common glass round pickle bottle, which can stand on the floor or table, on one side of the lanterns, out of the way, and the whole affair will not cost 6d, and yet answers the purpose admirably. Two pieces of compo. pipe, each 6in. long, must be fitted through a good bung in the mouth of the bottle, the inner end of one being flush with the bottom of the bung, and then curved to an elbow. The other must be thrust through the bung about half way down the inside of the bottle, and the outer end

If such men as Mr. Edward Henri Todé (who started, and for some time edited that journal), and who after wards started and edited the Fenian), and others like him, cannot be induced on moral grounds to forbear from publishing their filthy broadsheets, it is time for the law to interfere. I trust therefore you will allow these few lines to appear, that now, when there seems a chance of the matter being agitated, we, who are represented by you, may not incur the reproach of having remained silent.

TEST OBJECTS.

КАРРА.

SIR,-I send you a few of the tests that have been put upon a telescope in my possession. It is 3in. aperture, 4ft. focus, 3 eye-pieces of 35, 60, and 96 diameters. With the lowest power I can discern Jupiter's satellites before sunset, and with the highest power I have observed the transit of the satellites. It shows distinctly 4 stars in the trapezium of Orion, it splits Castor easily, shows the companion of Sirius, also Rigel; Cor Caroli it shows beautifully with the lowest power; Mizar also. I have seen the trapezium through a 3in. and 44in., and see 5 stars in one, and 6 in the other: The 3in. shows the belts of Jupiter more distinctly than a 74in. silvered glass reflector. If "F.R.A.S." can give me further test objects, I shall be greatly obliged.

There is no reason why every village church, if it has a bell, should not have a good public clock. A clever blacksmith, with a lathe and slide rest, could put such a clock as I have described, up in almost any town, for £25, if it only struck the hour, and make very good wages. The bearings for the spindles, I forgot to mention, were flat bars of iron, screwed to the wooden frames. The pivots work in brasses, rivetted in the bars. The pallets are made of sheet brass, and the 'scape wheel of steel. The pendulum bob is a cylinder of lead, weighing 15lb.

Allow me, Sir, in conclusion, to say I like the new shape the ENGLISH MECHANIC has taken, and that I hope it will continue to be successful! I have subscribed from the first, and have always endeavoured to make it known to my mechanical friends.

SYDNEY MADDISON, Hastings.
P.S.-I have no objection to indicating the place
where the clock may be seen; Partney, near Spilsby,
is the village, and the blacksmith who has charge of
the clock would no doubt be glad to show it to any
one who found it worth his while to go there.

I was engaged previously in putting up, in the tower
WILLIAM BAGULEY. of a friend's church machinery to strike the quarters

also curved to an elbow. This will be for the inlet for the gas. Now tie a sponge or large-sized argand cotton wick to the inner end of the pipe, on which a plug of wood or a cork with a hole through it is fitted tightly, so as to keep the wick distended, which will then hang

down to the bottom of the bottle. Pour in about halfa pint of benzole, not rectified, but what is sold as ordinary benzole by chemists, at about 18. 6d. a pint. Then close the bottle, and connect the inlet pipe to a gas branch (after taking off the burner), and connect the end of the outlet pipe with the pipe leading to both lanterns. This latter connection must not be of india-rubber tubing, but either compo. or flexible tubing (to be got at all gasfitters), as the india-rub

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tube absorbs the benzole vapour very rapidly, and
would spoil the effect. The action of this simple
apparatus will be evident, for the capillary action will
saturate the whole of the cotton wick or sponge, and
as the gas passes from the end of the pipe the pres-
sure will force it through the sponge or wick, and in
doing so it will take up the vapour of the benzole, for
which it has great affinity, and, passing out of the
bottle by the outlet, will burn in the lanterns with a
very fine white light, far superior to any oil flame, and
also very steady; but this must be the result of care-
ful experiment, and will depend on the relative length
of chimney and pressure on the gas main. I need
hardly add that every joint must be made perfectly
tight by cement or sealing-wax, and when done with,
the remaining benzole must be emptied into a good
stoppered bottle, as it is very volatile. Nothing but
very fine hole burners can be used with advantage
with such rich gas; and if "Adolescens" fits taps to
each burner, he can dissolve without using the ordi-
nary shutter or comb, leaving one burner Just alight,
while the other is turned full up. A small hole in
each lantern door with a coloured glass in it will en-
able him to turn on the gas to the proper height; other
wise, he will find a great waste of gas and bad light.
"V. W." may have used his plan by careful atten-
tion, but I am confident he would not get a brighter
light and better or more convenient arrangment than
what I have described, as I have tested it frequently,
and used it constantly in giving lectures, &c., for tho
last six years.

Alove is a rough drawing of the bottle, but fear that
I have already taken up too much of your valuable

space.

BARIC CHLORATE.

C. D C.

SIR,-As your correspondents "Taffy" and "Pyro" may wish to have some idea as to the sort of baric chlorate they will obtain, by strictly carrying out Mr. Davis's instructions on page 10, I append the probable per centage composition of the crystals it will yield. If allowed to cool to 80° C., and then the crystals collected:-Baric chlorate, 53 per cent.: baric chloride, 47 per cent. If allowed to cool down to 60 Centigrade: -Barie chlorate, 47 per cent.; baric chloride, 53 per cent. If allowed to cool to as low as 40 C. :-Baric chlorate, 41 per cent.; baric chloride, 59 per cent. If allowed to cool down as low as 20 C:-Baric chlorate, 33 per cent.; baric chloride, 67 per cent. Finally, if allowed to, as most probable, cool to 10 Centigrade (50 F.):-Baric chlorate, 27 per cent.; baric chloride, 73 supposed to be "pure" (?) baric chlorate would conper cent. Therefore, most likely, the salt obtained, sist of a mixture of 1 part of baric chlorate, and nearly 3 parts of baric chloride; while, if collected so as to yield the purest salt (i.e., containing only about 50 per cent. of impurities), over 60 per cent of the baric chlorate would be wasted and lost, as the mother liquid would contain from 15 to 70 per cent. of the baric chlorate formed, the exact amount depending on With reference to the three apparently contradictory replies furnished by Mr. Heard, Mr. G. E. Davis, and "Ernest," concerning hypochloric acid, they are "all right and all wrong."

the temperature.

U.

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SIR, I am glad to see that our old friend the ENGLISH MECHANIC is so strong and vigorous. As you have lately given the millers a fair portion of your time and attention, perhaps you will be kind enough to pay the like compliment to their brothers the farmers. In looking over some papers a few days ago which I brought from the Paris Exhibition, I found the enclosed, and the thought struck me that perhaps it might be useful to some of your subscribers; it might give some of them a hint which would set their thoughts in the right direction with regard to the improvement of agricultural implements. If you think the spader worth insertion in your valuable pages you will greatly oblige. S. KENT, Hastings.

COMSTOCK'S PATENT ROTARY SPADER. The spader is designed as a substitute for the plough in preparing the ground for seed in fields that have

been once broken and the sod rotted. It is not adapted | material may be mixed in proportion, as we may wish
to breaking prairie or meadow land, nor for land that to make a more or less bulky kind of fodder.
is not comparatively free from stones, stumps, and JOHN HUGHES, Analyst, 16, Penn-road-villas,
roots.
Holloway, N.

By means of tho lever on the foot board, it is readily put into position to work or travel, on the farm or road, and is easily controlled by any one capable of driving a team.

The teeth or tines on the fork-bars are about 7 in. apart, and when on the bar constitute what is called a fork."

1

NEW CARRIAGE BRAKE. SIR,-In your excellent journal of the 28th of January last there appears a notice of a new carriage brake. On reading the description of it, I was much surprised to find that a carriage or cart brake exactly self-similar in every way to that now patented by Messrs. Parry and McHardy was exhibited at the show of the Highland and Agricultural Society of Scotland held at Dumfries in the summer of 1860, and that to it was awarded a premium of £10. It attracted great attention, and was universally approved of. It was made and shown by Mr. Thos. M'Cririck, agricultural implement maker, Old Cumnock, Ayrshire, who has long been well and widely known in the south and west of Scotland for his many useful improvements and ingenious and original inventions in connection with agricultural machinery, but whose diffidence of disposition (which is so frequently found allied to true and original genius) has hitherto kept him from patenting any of his many inventions; and as he has Dow considerably passed the allotted span of threescore years and ten his career as an inventor may be said to be over. Still it is right that he shonld not be robbed of any honour which justly belongs to him; and undoubtedly he is the original inventor of "the new carriage brake" described in your journal of the above date. Messrs. Parry and McHardy may not have seen Mr. M'Cririck's brake, and they may have been original inventors also; but even if such has been the case, they have been forestalled in it by Mr. M'Cririck by nearly ten years.

The teeth or tines of the fork are cast steel,
sharpeners, of the simplest possible form, 8in. in
length, and are secured to the bar by a clamp, or
stirrup, and wedge, and can be taken off or put on in
the field by any person, as each tine and stirrup will
fit the fork-bar of any sized spader. Great care has
been exercised in determining the strength necessary
in these parts; but if broken, and no extras are at
hand, may be replaced by any good blacksmith.
A team in ploughing a furrow one foot in width
travels 8 miles to each acre (besides turning corners),
or 16 miles in ploughing two acres, which is a good
day's work for both team and man, and is not always
well done with a furrow of that width; if a narrower
one is turned, the travel is increased. The five tine
spader works three feet in width; therefore six acres
are spaded to 16 miles travelled, or as much as three
pair of horses, three ploughs, and three men will do
and but 275 miles of the team is required to spade 100
acres; making a garden bed of the grain-field at less
than half the cost of ploughing; and this may be done
by any one able to sit on an easy seat and drive the
team-no walking or other labour required.
The saving in expense of teams and manual labour
alone soon pays the cost of a spader, even to smaller
farmers.

Other advantages may be enumerated as of equal, if
not greater, importance than the saving of labour and
cost.

As the ground can be prepared in much less time, it may be done at the right time-and less time is given for the soil to settle and pack, and for seeds of weeds to germinate and take root before planting.

The attention of nursery men and market gardeners is invited to the fact that by twice going over lumpy ground with the spader the soil is better and more cheaply pulverised than can be done by any other process.

It will pulverise the soil and leave it light and melthe plough. And on sticky soils, where the plough low when too wet to be worked, without damage by will not scour, it will do its work perfectly.

THE ADVANTAGE OF USING CRUSHED
OATS.

which have been previously crushed and partially
SIR,-The advantage of using oats, beans, peas, &c.,
ground into a coarse powder, is not as generally known
as it should be; I therefore take this opportunity of
drawing the attention of those of your readers who
are interested in such matters to the following pra c-
tical illustration of an important fact, namely, that
but little good can be expected from the best descrip-
tions of food unless its mechanical condition is also
attended to.

Some days ago I procured a small load of horse dung.
which, being taken from the streets of London, was
perfectly free from any loose particle of hay or straw.
This manure was put in a heap in my garden, and
covered over with a thin layer of earth.

In about a week afterwards I was much surprised to see quite a crop of green shoots coming up on the surface soil, and on making a carefnl examination at the rootlets, I found that in each case these shoots proceeded from what had originally been a sound grain of oats.

It would be interesting to know to what extent, and under what special circumstances, oats and similar cereals are passed off unaffected by the ordinary process of digestion, &c.

It certainly appears to me very desirable, in order to feed animals with the greatest advantage and profit, that the different kinds of food should be carefully reduced to a fine state of division, then steamed, or at least moistened, after which chaff or similar coarse

A photograph of the brake, and of the cart to which it was attached was taken at the time. Could we have obtained a spare one, we would have enclosed it; and we may do so yet, when more of them are taken.

A. B. TODD, Old Cumnock, Ayrshire.

THE SUN.

corre

SIR,-The ENGLISH MECHANIC of the 1st April, 1870, has just come to hand, in which I have noticed a letter that bears the initials of "S. B.," who says he was in hopes that some of your "qualified" because a fraction is a part only of a whole. It spondents would have answered "Veritas." "The 1005998 is a fraction. This is not the case,

"S. B." had stated that 1005998 was the proportion, ratio, or quotient of two distances or values, he would have been nearer the trnth.

Mr. "S, B." has one fundamental error in his calculation of the mean diameter of the sun-namely, he whereas, he ought to have used the mean semi-diameemploys the equatorial semi-diameter of the earth, ter in order to arrive at a mean value of the sun's

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BOOKBINDER'S CUTTING PRESS. SIR,-I send a sketch of a bookbinder's cutting press, although I firmly believe it will be "Love's labour lost," for those whose trade it is to provide bookbinders with cutting presses do not always turn out a good press; but as Maschil" and others have inquired about the apparatus, I thought it would perhaps be best for the interests of "our" MECHANIC to comply with their wishes. Persons out of the trade seem to form the most erroneous ideas of bookbinding. gilding leather, &c. I should much like to see some

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tightly fixed, which causes the cheek A to recede from
or approach to the cheek B. GG are the heads
of the two screws, through which are two holes,
about of an inch in diam., in which the press-pin, or
lever, which is about 20in. long, is inserted. H H are
two strips of hard wood, placed about 14in. apart, for
the plough to traverse .in. The cutting press here
shown, is 2ft. between the screws. II are two guide
rods, firmly fastened in the cheek B, which keep the
cheek A in its proper position.
AB INITIO.

THE "ENGLISH" VELOCIPEDE ON A NEW PRINCIPLE, AND OUR ENGLISH ROADS. SIR,-For many years my attention has been directed to the subject of velocipedes, both theoretically and practically; and when your third volume was coming out I saw it was treated of therein, since which time I have been a subscriber.

The wheels, as will be seen in the drawing, are
rather small, the driving wheel being only 2ft. 8in.,
and the others 2ft. 4in. Some will very likely think
they are too small; but those who have made great
use of the velocipede on all kinds of roads will never
prefer them much larger.

The frame of this velocipede consists of angle Iron
It is filled
bent in the forepart to a curve, as shown.
One end of
in with wood. They are in four parts.
each goes right across a strong board, to the under
Above this
part of which it is bolted by two bolts.
board is the seat, between which is the box, secured
by a lock and key. There are no springs, but a good
cushion on the seat, and I can affirm that I have not
experienced the slightest unpleasantness as regards
jolting, jogging, or shaking (I have gone over rough
roads); indeed, it is rather otherwise, for it is truly
comfortable to ride, as I have said above. Another
noticeable feature in this machine is the guiding han-
dles being placed at the sides of the seat. This allows
the chest more play, and gives greater opportunities
of development than when the hand has to reach fer-
ward to guide.

This latter remark leads me to refer to the worker
of the velocipede. It may be said that the velocipede
will never compete with the railway train as an econo-
miser of time. It may be so; but it can also be said
that the railway train will never compete with the
velocipede as a promoter of health. So the velocipede
question, in this respect, resolves itself into these
two points, time or health, not considering the saving
of railway fares. Time is no doubt valuable, but health
is still more so-it is invaluable; it is a fortune in
itself. What truly wise man would, for the sake of
saving time, always avoid opportunities of promoting
his health? As vigorous health means greater capa-
bilities for business, it is questionable whether the
right use of the velocipede is not more favourable to
the attainment of wealth than otherwise.
I will conclude what I have to say on the question
in another letter, next week.

A THINKER.

THE ENGLISH MEC HANIO." An Old Subscriber" writes: "Allow me to congratulate you on the decided improvements recently made in the ENGLISH MECHANIC. Issuing the index with one of the numbers, separating the advertisement sheets from the body of the work, giving the contents on the outside page, increasing the size and at the same time improving the form of the publication, giving a list of the new patents -these, with what we have had before, combined with a greater variety of contents, and, I think, a certain sifting of the Notes and Queries department, make the ENGLISH MECHANIC AND MIRROR OF SCIENCE the principal scientific journal published. You need not stoop to the miserable and deceptive manœuvre of offering to give away prizes

for nothing,' in order to bolster up an artificial circulation; you can stand on your merits."

[graphic]

me

BENNETT'S DIE CHUCK -Edwin Baker writes:"Will you allow to correct an error in last week's number, with respect to Bennett's die chuck? Mr. Bennett invented and made that chuck while he was in the employ of the Messrs. Holtzapffel, and not Mr. Evans's, as it was given us to understand. I question if Mr. Bennett ever was in the employ of Mr. Evans at all,"

Cover

A GOOD RECIPE FOR HOME-MADE YEAST OR BARM.-Place a quart of malt in some wooden vessel, boil one ounce of hops in three quarts of water one hour; when clear from the vapour arising therefrom your over the malt so as just to scald it. over with thick flannel or baize till morning, when it should have a frothy fhead on; strain. Put half-apint of this liquid to 71b. flour, set your sponge over night, in the morning mix and bake in the ordinary way. This is an excellent recipe, and was given me by the late Sir Charles Napier's cook. Nothing can equal the sweetness of bread made from this.-W. I.

MEDICAL OPINION-Dr. Burdwenii in a letter says:-"I love your MECHANIC, but I dislike to see medical questions, and often very absurd ones, asked through it. It is almost impossible to give an opinion without seeing the patient, and in most cases it would be dangerous to act on good avice given under such circumstances."

NAME OF STAR.-"Conjecto" writes:-"Allow me to thank Omicron' (page 656) for the (probable) name of the star which I saw in conjunction with Venus on the evening of the 3rd Jan. I am somewhat surprised that no other mention has been made of this (to me) most interesting sight. I have watched many occultations of stars by the moon, but have never been so pleased as with the beautiful appearance presented by Venus and this star, which I watched from the early evening until they disappeared together behind the distant tree-tops. The star was at least as bright as Jupiter's 3rd satellite, and shone with a steadiness quite remarkable for a fixed star."

TO MAKE GOOD BARM.-"T. S. T." says:-"Boil loz. of good hops in 2 quarts of water an hour. When strained and milkwarm, add lb. of brown sugar and lb. of good mealy potatoes previously boiled and squeezed stone jar, and place by the fireside for one day and two nights. When it has done working put in a handful of salt, and cork the jar tight and place it in a cool corked after pouring any out. It is well to add a fresh place. This you may use immediately. Keep it closely quantity before the whole is used. It will keep as well for use when made six months. At about four o'clock set your barm-that is, get two or three potatoes (or one good large one), mash them up very fine, put them in a sieve and strain about three pints of lukewarm water over them into a crock (throw away the remainder), then throw the barm down on the top of this, then shake a couple of handfuls of flour on the top of this, and cover with a cloth and let stand before the fire till about 9 o'clock-by this time it will have risen, and fallen a little again. A regular quiet heat must be kept to it. At that hour throw a little salt through the flour, mix the barm well through the flour, and if too dry add a little warm water. Work it up until "J. K. P." also writes:-"Under the above head-quite fit to put into the oven. Next morning, when well risen, divide into loaves (two quarts of flour to a ing, on page 23, you state a German mile at 1806 yards. Now a German mile is what they call a 'stunde or loaf). After making the loaves, lay them on the board hour, i.e., an hour's walk, and Adcock's Pocket and cover with a cloth for about twenty minutes. Do Book gives 10126 yards, which agrees with Cham- not shake any flour on them at night after mixing the bers' Encyclopædia." Adcock states the Turkish mile barm in the evening. About fourteen quarts of flour at 1826, while you give 1626, and I have no means of to this much barm (three pints of made barm) -Buns for breakfast: 1lb. of flour, whites of two eggs, 2oz. telling which is right. A German short mile' is 6859 yards according to the ' Imperial Dictionary,' and butter, two spoonsful of barm; mix together with milk to a light dough, put at the fire for one hour to is quite enough for an hour's walk for me." rise-five minutes will bake them. Mix as for a cake.'

I will be as brief and as plain as I can in what I am about to say, for my aim is the diffusion of clear views of the correct principles of velocipede construction, and to assist in its inauguration as a really useful machine. I have had several inachines made on different principles and designs. One, a three-wheeler, had two driving wheels, between which the rider sat. It could be worked up hill pretty well. Afterwards-thinking that if one were made for two to work, sitting back to back, it would be easier to get up hill, I had one made for two; and what was the result? Why, the very reverse anticipated! Two could not possibly work it up anything like a bill, and, strange to say, one could! This was about two years ago, since which time I have endeavoured to trace the reason of this; and about twelve months since I succeeded in what I thought might be some explanation of it. Suppose a man had to take two sack-loads of potatoes (weighing, say 5cwt.) a mile, and he had before him the choice of a wheelbarrow and a truck (a two-wheel handcart) to take them with; and granting that the truck weighs EXTRACTS FROM CORRESPONDENCE. as light as the wheelbarrow, which should we suppose he would choose? Common sense would say the truck, because he could balance the load on it, and all INTERESTING FACTS." Pneuma" writes as he would have to do would be to roll or wheel it follows:-" In your number for March 25, page 23, along. In the case of a wheelbarrow, he would have is a small paragraph headed Interesting Facts,"" to lift half the load before he could wheel the other among which are two or three statements which half. Now, as wheeling a load is easier than carrying perhaps you will allow me to correct. The German a load, it is evident that the wheelbarrow is a foolish mile is much more than 1800 yards. The German vehicle where a truck can be used. Let us look again short mile is 6859 English yards, and the German long at the above velocipede. We see that the spokes of mile 10126 English yards, and the Hanoverian mile The greatest the driving wheels act similarly to a man's legs in a 11559 yards (see Kelly's Cambist'). On the 15th wheelbarrow, with this difference, that whereas in a depth of the sea is more than 4 miles. wheelbarrow a man's legs have only to overcome the November, 1849, Lieutenant (now Captain) Maury, in friction of half the load, in this machine the wheels the 'Fancy, let out 5700 fathoms of line (about 6 miles) have to be made to overcome the friction of nearly the without finding a bottom. This was in lat. 31° 59′ N. whole of the load before it can be moved. Again, let and long. 58° 43′ W. This depth exceeds the height us now look at the truck. Its two wheels act as guid- of Mount Everest, in the Himalaya, by a mile. ing wheels, at the same time bearing the load, and the statement respecting the English acre is evidently man's legs act as the spokes of a driving wheel. Now, 69yds. 1ft. 10in. each way." wrong. It should read 4810 square yards, being if a velocipede were made on this principle, the question would be, Would it be easier to propel than the other? I was soon convinced that it would; and having proved it to my own satisfaction, I have laid down this maxim or principle as being the correct one in the construction of all velocipedes-viz., that no more weight should be placed on the driving wheel than is actually necessary for driving purposes. To illustrate this still further, take the case of a luggage train. Suppose that instead of the locomotive drawing its load of 200 tons behind it, the whole of the 200 tors were to be placed right over and upon the driving wheels of the engine, what would be the following." Will you allow me to point out one or consequence? Why, the power of any ordinary locomotive would most probably fail in endeavouring to overcome the enormous friction caused by the load above. Observing the above principle, I designed the following velocipede, which at a glance will be perceived to be self-adjusting as regards the load on the driving wheel. It also meets every other requirement that is looked for in the velocipede-viz.: 1st. It is light and simple in construction and working. 2nd. It is perfectly safe, easy to work, and comfortable to ride. 3rd. It is easy to guide, and with all the wheels being free of each other. it turns sharp corners. 4th. It has a minimum of friction consistent with a maximum of power, as both hands and feet would be used; but I never found it to require more than the use of one hand with the feet up the steepest hill, the driving wheels not slipping.

The

DR. USSHER'S ADVICE.-Hy. Good sends us the two errors in 'Dr. Ussher's Advice?' First of all, it is not Dr. Ussher's, for I have now before me Cow

I am

per's Poems, in which I pasted a label more than
thirty years since, a copy of which I enclose.
quite sure that it is an oversight of the doctor to

For oft-imparted knowledge doth
Diminish learning's store."

FREE SCHOOLS OF INDUSTRIAL ART.-A say-plan is now before the Massachussets State Legislature, U.S., by which every town of a certain size will be compelled to maintain, in connection with its town school system, an evening school for education in "the industrial arts." These evening schools will be open two hours on five evenings in the week, with a competent master or mistress for every 25 pupils. Travelling loan collections of models andcasts of works of art and design are to be formed, the expense of which will be borne by the commonwealth. A monthly system of examinations is also proposed, with the exhibition of

You will also observe that the words 'I often lent'
should be it often lent.' If some of your subscribers
would get up a neat label of the above, either in litho-
graphy or photography, leaving a space for name, I
think they could find a sale for them."

"

VARNISHING THE VIOLIN. -"St. George" writes:-"I find amber varnish to injure the tone of the violin the least of any that I have tried."

meritorious works.

REPLIES TO QUERIES.

lb.

has not suffered from the malady from that day | The content may also be found by obtaining the solidity
to this.-ED. £. M]
of the middle cylindrical part, then that of the semi-
circular ends, and adding the two results together;
but I think "A Diver" will find the rule given above
more concise.-WILLIAM MOOR, Jun., Hetton Colliery.
[2097.J-STAINING WOOD BLACK-Boil
of chip logwood in 2 quarts of water, add loz.
of, pirl-a, and apply it hot to the work with
a brush. Then take lb. of logwood, boil it 28
before in 2 quarts of water, and add oz. of ver-
digris, and foz. of copperas; strain it off, put in
16. of rusty steel filings, with
this go over the
work a second time. Oil of vitriol diluted with water
and applied with a brush makes a good black stain.-
GUILLAUME.

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ZINC PLANT. In reply to "Saul Rymea's" question to me, his idea of the rationale is correct. All the descriptions given relate to the lead tree, and of course the more lead salt there is in the water the more vigorous will be the growth of this specimen of metallic growth. A true zinc tree would require the use of a more oxidisable metal in a zinc solution, and as the action of such metals as magnesium, sodium, &c., would probably be too rapid, the metal would be more likely to be thrown down as a non-adherent powder than as coherent crystals. The process is a true electric one when the "plant" is formed, the electricity acting at the extremities of each deposited particle, and producing there the crystalline deposit. Other metals may be thus deposited aleo, and the nearer alike the affinities of the two metals are for the acid holding the one in solution the slower and more-in. perfect the action.-SIGMA. 16

[1708]-HEATING GREENHOUSES BY GAS.In reply to "Professional," p. 637, I beg to say that I shall be glad indeed if he can point out a plan by which gas may be used in the heating of greenhouses, so that it may be done with some degree of economy. He has, however, a much better chance of doing so than I have, as with him gas is charged 3s. 6d. per 1000ft, but with me it is 68. 3d, in itself a mighty difference. I have long thought that our gas company is extortionate, but they maintain that the superior quality of their gas, made from Cannel coal, makes it as cheap to the consumer as gas from other coal at half the price. This reasoning may suit their dividend of 10 per cent. per annum and a bonus besides, but I must acknowledge I don't believe in it. "Professional" suggests that it may be the arrangement, and not the material, which causes the failure with me. I shall endeavour as briefly as I can to explain my apparatus, and then he may judge for himself. It consists of a small copper boiler connected to about 64ft. of 3in. iron pipe. The boiler is a cylinder, the under end, as it were, pressed in to form a concave for the flames to play upon. Enveloping the boiler is an iron jacket allowing a space of about 2in. between it and boiler. From the top of the iron jacket a 31n. iron flue is carried away so as to take off the fumes of the burnt gas, and also to radiate as much heat as possible. This flue is carried the whole length of the house, and then passed outside. The gas is applied at the bottom of the boiler by three of Buusen's burners, so arranged that either one, two, or three may be lighted at one time. I find that in severe weather it required the whole to be lighted, and on these occasions, supposing they were lighted at at 4 o'clock in the afternoon, and were kept burning until 8 o'clock next morning-16 hours-it consumed about 400ft. of gas, which cost me 28. 6d. The apparatus worked well and gave little or no trouble; the only drawbacks were want of heating power, except a very large quantity of gas was consumed, and the injurious effects the fumes had upon the plants. This latter objection could be remedied by keeping the gas entirely out of the house, but this would necessarily entail a certain amount of loss of heat, which could only be made up by a greater consumption of gas. I suspect others have come to the same conclusion as I have done (I notice the reply of "J. B.," p. 12, vol II., &c.), but if "Professional can preduce a plan by which gas may be used with a reasonable cost, and at the same time to give a sufficiency of heat, I am sure he would confer a favour on several of us amateurs, as there is no doubt that the little attention gas requires gives it in that respect a great advantage over other modes of heating. AMATEUR,

3

[1908.-ETCHING RAZORS. For H2SO, read
H2SO4.-F. B. KNOX.
[1967]-PESTLE AND MORTAR.-Sulphuric acid
is the best thing he can use.-A MECHANIC.
[1970]-VARNISH FOR IRON PATTERNS.
N. L." gives an excellent reply to this query, but he
forgot to say that it was raw linseed oil that should be
used, brushed on like paint. Should the pattern be
required for almost immediate use, coal tar naphtha is
very good, and it dries quickly without heat.-METAL
HEAD.
[2007]-TEMPERING DRILLS. Surely your
printer must have misread S. T.'s" answer, which
is exactly the opposite to what he must have meant to
state, and which, so far from hardening drills, would
anneal and soften them. Let me add to my former
reply to this query: That for small drills, say to
diameter, a candle is the most convenient
means of letting down the temper, as the mild heat
tiut can be obtained with certainty.-J. B.
causes the colour to change so gradually that the exact
[2018.]-MULTITUBULAR BOILERS.-Tubes ia
boilers of this kind should have a ring on one end, say
boiler first, and caulked. In ordering the tubes, he
in. thick; the ring may be put in the end of the
could order them bulged at the factory, about 1-16in.
The advantage of the ring is that if the tubes should
scale they can be knocked out from one end.-MILLY.
[2043,]-PILLS.-Not only pills, but (that most
nauseous form of medicine) powders may be taken by
any one without the least difficulty. Buy at any con-
fectioner's a sheet of the wafer that they use for rati-
fees, costing one halfpenny. This is 8 or 9in. sq, and
is to be broken up into squares of an inch and half or
two inches. Take one of these, dip it in water, and
lay it on the palm of the hand, where it instantly
becomes as limp as a rag and as slippery as an oyster.
Lay your one or more pills, or your powders, in the
centre, and fold the wafer over it, put it on the tongue
where it lies flat, like an oyster, and a sup of water
takes it down without taste or trouble. This method
is always practised in Germany, and has been in use
in my house for twenty years, and, strange to say, I
have never met any person, medical man, or druggist
in England who seemed to have ever heard of it. It
is perfectly effective, within reach of the poorest, and
ought to be more generally known.-G. NASH, S.
Michael's Vicarage, Louth.

[2044.]-REPOLISHING STEEL WATCH CHAIN.
"H. B.M." should rub his chain between his hands,
dusting them with fine flour of emery from time to
time; he will soon get it tolerably bright, then fasten it
to his bunch of keys which he carries in his pocket,
and the chain will soon become burnished. Proved.
-F. H.

[2055]-COIN OR COUNTER-My statement on p. 20 is incorrect; as stated by Mr. Batty, the pieces referred to are certainly weights.-HENRY W. HENFREY, M.N S., &c., &c.

[2059.]-CEMENT FOR AQUARIUM.-1 India-
rubber, 12 mineral naphtha or coal tar heated together,
add 20 of pounded shellac. When required to be used
heat to about 2609.-BLUE RUIN.

[2062.]— SODA WATER BOTTLING MACHINE.
to do so myself. In the first place his leathers are too
-Seeing no one answer T Harding, I will endeavour
thin, and the hole in the washer should not be smaller
than the cone where the corks are put in; again, have
them serewed up tight. I have been in the habit of
buying a soldier's belt (an old one), and making them
myself. One lasts me nearly two years. Since I have
used them, now nearly ten years, I have never had the
bother T. H. complains of. If he wants any further
information, I shall be glad to give it.-J. T. BAILEY.
[2038.]-CONTENT OF IRON PANS.-In answer
to "J. R. W.," taking the depth of the pan as h,
diameter as d, and V as cubical content of pau,
3·1416.

[2098-DISCONNECTING STEAM PIPES.-Putting brown paper between the flanges and the indiarubber washer will keep it from adhering to the iron. I have found this to answer well.-ABERDEEN MECHANIC.

[2098.]-DISCONNECTING STEAM PIPES.-Canvas steeped in red lead is frequently used instead of india rubber; or if the flanges have been faced, a little plain red lead will do. Another way.-Steep plaited gasket in whitelead, and by working it in the hand it may be used several times; or, instead of whitelead mix blacklead with boiling oil into a paste and work well equal parts of redlead and whitelead with fine metal into the gasket; if the flanges are rough or uneven, borings. In using gasket, canvas, &c., care should be taken that the ends do not overlap, but meet nicely. BLUE RUIN.

[2110] TO REMOVE RUST.-Plunge the hooks into a bath of diluted hydrochlorie (muriatic) acid, say 1 pint of acid to 1 quart of water. Leave them there for twenty-four hours, then take them out and rub them well with a scrubbing brush. The oxide will come off like dirt under the action of soap. Shoul any rust still remain, as it is likely in the corroded parta, return the hooks to the bath a few hours more, and repeat scrubbing. Afterwards well wash in plain water several times and thoroughly dry before a fire. Lastly, a little rubbing with oil and fine emery powder will restore the polish. Should grease have mingled with the rust, it is necessary to remove it with a hot solution of soda, before submitting the metal to the acid.-GUILLAUME.

[2116.]-WATER POWER.-I find that my answer to this question last week had reference to 200 cubic feet of water per minute falling from a height of 30ft.. whereas the question was: What would be the power of 200 gallons per minute falling from that height? The answer should have been 14 h.p., reduced to a useful effect of 1-— h.p.-C. S.

1

6

[2117.)-CEMENT FOR IRON ROOM.—“ T. S. H." will find the following to answer his purpose: 1 bushel of sand, 4lb. of red lead, 1lb. of whiting; mix up with boiled linseed oil and a little boiling water.-SWEEP Ho.

[2119.]-CLEANING PIANO KEYS AND TEETH. -If the discolouration does not extend much below the surface, the ivory may be scraped till something like its original condition is obtained, then smoothed with very fine glass paper, aud finally polished with a leather buff and whiting. As to teeth, if Ilex" means natural ones, which have simply obeyed the laws of nature, I with him should be glad to know of any to their present or future usefulness, but such a remedy means to restore their pristine whiteness without injury I fear, will be as easily obtained as a mill for grinding old age into youth.-F. F. C.

[2121.]-BOILER TAP. -- Had "Gilder" followed the suggestion of some of our correspondents, adding proved," he could not have recommended emery and less. Let" R. A." pound a piece of freestone, and sift oil. It will not stop the leaking, but make the tap useit through a piece of coarse packsheet. Mix this with water and grind it, adding no sand, but keeping the plug wet for five minutes before drying the plug and bill. This, if properly done, will make the tap perfectly tight. Proved-CONICAL PLUG.

[1820]-HOW GLASS FOR CHURCH WINDOWS IS FIRED.-When the windows are painted with the requisite colours, they are placed in an oven much resembling the ordinary bakehouse oven. Around this oven are iron shelves, upon which are placed large iron plates very level; on these plates the glass from the windows is placed; the oven is then very gradually heated. The beat is adapted to the nature of the colour required; if the flux is hard the heat is much greater than when soft. This requires great nicety, and perfection can only result from much practice. It sometimes happens that one or two moments of too Again, cubical content of globe, taking d = diameter chisel-and apply to J. Blakeborough for a patent tap,

prolonged an heat, will spoil an entire batch of window
panes, turning the colour from what was intended as
a bright yellow, to a dirty brown. When the oven is
got to the required heat, the calculation is made by
the man who has charge of it as to the duration of
the heat; this is very carefully watched, then when
the glass has had sufficient fire, the oven is stopped up,
the bars from the grate drawn out, and the whole is
left to cool gradually to prevent cracking. When cool
they are then washed with water, the ochre comes off,
the beautiful stain remains. The heat required is a
little over that of redness, just approaching a white
heat, but modified according to the nature of the
colouring materials.-JOSEPH LEICESTER.
[1871.]-BLOTCHY FACE.-I have just perused Mr.
Johnson's reply as above, in answer to a "Sufferer
from Blotchy Face." It is certainly good sound ad-
vice, but not a remedy for this disagreeable ailment.
Four years back, having been troubled with it in a
violent form, I was induced to pay a visit to the late
Dr. James Seaton Smith, of Liverpool, surgeon of the
Skin and Cancer Hospital in that town, for the pur-
pose of getting a remedy for it. His remedy was the
enclosed, coupled with good and plain diet, which
put me to rights in two months. The recipe was
dear (£2 28.), but it was effectual. Let the gentleman
interested give it a trial, and kindly let me know the
results through your columns. Sol. arsenic chlorid,
1dr.; tinct. ferri perchlorid. 1dr.; tinct. rhu. 2dr.;
lig. zarafar 4dr.; aq. pur. 12oz. Ointment-Megt.
plumb. iodid. 11dr.; to be applied outwardly.-FORTU-
NATUS.-[A friend of ours, many years since, was
troubled with pimples on his face, and particularly
under his eyebrows and moustaches. He consulted
several country doctors without deriving any benefit.
He tried the hydropathic treatment, with the same
result. He came to London, and consulted one of the
physicians of the Cutaneous Hospital, Bridge-street.
Blackfriars, and was cured in about a fortnight; and

= ... V

V cubical content

π

-

6

(3d 2h) h2

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BLUE RUIN.
[2084.]-GRANITIC PAINT.-"S. T.," in his reply
in your last week's number, is in error as to this paint.
He states that the menstruum employed in it is silicate
of potash, to harden and combine it with the pigment
with which it is admixed. The granitic paint of the
Silicate Zopissa Composition and Granitic Paint Com-
pany, of 39A, King William-street, City, contains no
silicate of potash, and is well known to dry and harden
in a manner superior to any paint yet manufactured.
The statement of "S. T.," if uncontradicted, might
do us great injury.-THOMAS CHILD, Manager.
[2093.]-BRAZING CAST IRON.-The only method
of brazing cast iron is to fit the broken parts exactly
together in moulding sand, then pour melted iron
over the parts to be joined, and when cool chip off
the superfluous iron. If properly done the joints will
be difficult to detect -BLUE RUIN.

[2094.]-SUBMARINE LAMP, &c.-I send the fol-
lowing reply to the second question of "A Diver,"
under this heading, viz., to find the solid contents of a
vessel with semicircular ends:-
Let Full length of vessel
d Diameter

Then

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8 = Solidity

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[2121]-BOILER TAP-I should advise "R. A." to take his tap out-he may do so with a hammer and which he may fix himself. It will not leak for years; and then it can be made good without taking it off. Address J. Blakeborough, Commercial Brassworks, Brighouse. Yorkshire.-SWEEP Ho.

[2126.]-JOINING WIRE.-"E. H. B." will make the best connection by first cleaning or scraping with an old kuife three or four inches of the wire ends; cross them at right angles, hold firm with a pair of pliers, and twist the ends tight around each other; then solder with rosin.-SWEEP HO.

[2131.]-PUMPS.-In reply to A Plumber," although bine may be made to receive a supply of from 40 to 50 this does not seem to me to be plumber's work, a turgallons per minute (say 45) with a fall of sft, and to deliver water at a height of 70ft. above it at the rate of 3 galious per minute. This is a small quantity, but it is as much as can be done with the power and under the circumstances named, A water ram would be a more suitable appliance, and would cost less. It would deliver about the same quantity.-C. S.

[2139.]-BOILER.-If John Jones will state, through the MECHANIC, the length and diameter of the boiler he intends to put down, and what is the greatest height he can put his water-tank from his steam boiler, and the pressure of steam at its highest point, I will send him a rough sketch of a self-acting feed that I have at work at present on two boilers working at 151b. per square inch -ANTI-EGYPTIAN.

[2143.]-SOFTENING CAST IRON." G. B. K. cannot soften cast iron. But by chipping off the surface or skin with a chisel he will find it easier to cut subtract-BLUE RUIN.

Or, in words:
From three times the total length of vessel
its diameter, multiply the result by the square of the
diameter and by 2618 for the solidity.

If = 10ft., and d 4ft., we have
8 = 16 x 2618 (30 - 4)

= 16 x 2048 x 26

= 108-9088 cubic feet.

[2152.]-PAINT ON BICYCLES.-Grind the dry colour; thicken with good pale copal varnish, then thin with turpentine; lay on evenly with commou paint brush. This should have very dull appearance, and dry very hard. When thoroughly dry, varnish with good pale copal (or carriage) varnish; put in a warm

place, and away from dust (after varnishing), until thoroughly dry.-W. H.

[2160]-PRESSURE ON COLUMNS.-If"W. R. E." will give the length of columus, and state whether they are compose i of cast or wrought iron, I shall be happy to answer him.-BLUE RUIN.

(2160]-PRESSURE ON COLUMNS.-This question cannot be completely answered in its present form, as the weight of the columns is not given. The following figures, from the "Engineer's Pocket Book," may, perhaps, suffice:-Solid cast-iron columns, 34in. diameter, will each bearHeight in feet | 8 6 1 1 10 1 12 14 | 16 Load in cwts. | 282 | 214 | 191 | 172 | 156 | 136 [2160]-PRESSURE ON COLUMNS.-According to Molesworth, the breaking-load distributed equally on

-J. B.

34

376

[2183.]-TAXIDERMY.-There are a few chapters on the above, as well as on skinning and preserving birds, reptiles, fishes, &c., at the end of Beeton's Book of Birds," which may be ordered through any bookseller.-VIVIS SPERANDUM.

have sometimes to wait a considerable time, I generally manage to get what I am in search of.-H. B. MILLER.

SPERANDUM.

12215.]-BRONZING BRASS.-Some time since, I asked through these columns how to bronze the fer[2184] SULPHATE OF LEAD BATTERY.- rules of fishing rods, without eliciting any reply, I Some time ago I decided to fit up my house with some fortunately found a tradesman who kindly told me, and I succeeded perfectly in giving the brass an appearhalf a dozen electric bells. I got all the apparatus I required from a firm at Halifax, except the battery.ance of real bronze. The recipe is, ld. of oxide of but took some time to consider this matter, as I wanted iron (rust), 1d. of arsenic, mixed in a pint of hydroone which would fulfil two conditions-cheapness and chloric acid. Clean the brass well to get rid of lacquer constancy. I at last decided upon a sulphate of lead, or grease, and apply with a brush until the desired colour is obtained. Stop the process by oiling well, one which I must say has answered perfectly both. I made it up myself as follows:-I obtained 6 glass when it may be varnished or clear lacquered.-VIVIS pickle jars and 6 porous cells, I then made 6 cylinders of thick sheet zinc to go easily into the glass cells. [2218.]-GEOMETRY.-Theor.: three circles being I got some No. 8 copper wire and wound into spirals to given, the lines respectively tangent to 2 of them fit loosely into the porous pots. After placing them have their intersections on the same straight line. all in their proper places I mixed up some sulphate of "X. X." asks a geometrical proof: perhaps the following lead with water and nearly filled each porous pot. I might satisfy him Draw a plane through the 2 centres; on each side of this plane we can construct the top with clean water, adding some crystals of one tangent to the 3 spheres constructed on the circles; Tidman's sea salt, and after connecting the copper these 2 symmetrical planes will cut the plane of the spirals of the one cell to the zinc cylinders of the next centres on the same line. Now, supposing 3 cones all through the series, leaving a zinc unconnected at respectively tangent to 2 spheres, those 3 cones will be one end and a copper unconnected at the other end, langent to the 2 planes, and have their vertices on their the top of my cellar and connected the wires comit was all ready for use. I placed it upon a shelf at line of intersection, and those vertices are the intersections of the tangents to the circles. Other demonstramunicating with my six rooms and bells. It is now tion, Analytic, v. Salmon, "Conic Sections," No. 117.nine months since it was set going and appears BERNARDIN. as good now as at first. It cost me for material about 15s, the cells are quart size, I am very proud of my handiwork, and believe it quite as good and far cheaper than the trade would have supplied me.-A

all four columns = 596——— whereby L is the length then filled each glass cell within an inch and a half of

L

1.7

of a column, assuming L to be greater than 15 times the diameter of the column. The calculation is easily carried out by means of logarithms.-A. ToLHAUSEN.

(2162)-SEAMSOF MACKINTOSH-If "G. W.D." will refer to reply 1777, page 613, Vol. X., he will find that 1 there stated that I found" Kay's Coaguline" (Kay, Bros., Stockport, 6d. per bottle) answer my purpose in mending the seams of my mackintosh, which statement I confirm.-W. H. I. P.

[2162]-SEAMS OF MACINTOSH.-Nothing is better than india rubber dissolved in naphtha.-J. B. [2169.]-PROBLEM.-Through A draw A F parallel

A

H

to B C, and equal to the difference between AC and
A B. Join C and F, and produce C F and A B to meet
in G. Bisect & Cin H, and join G H by a line cutting
Ain E. Through E draw DEI parallel to BC, and
DF is the required line. For since A FAC-AB,
and the triangles ACF and ECI are similar, as also
ADE and ABC, EI EC-DB. But since B H
IC, and D I is parallel to B C D E EI.
Then DE EC DB as required.-T. BROWN.
[2170.1-AN UNANSWERED QUERY.-I beg to
inform "Gitche Manito" that I replied to this question
some time ago. It is the opinion of the best numis-
matists that copper coins should be left alone, or at
most simply washed with soap and water. Cleaned or
WHENFREY, M.N.S., &c., &c., Markham House,
Brighton.

GOOD BOY.

[2188. VELOCIPEDES, &c. -In every case a driving wheel above 36in. becomes a disadvantage; the greater the diameter of the wheel above 36in. the greater the disadvantage. Treading is the best mode of driving, for when the foot is pressed on the treadle the weight of body then ceases to be the load and becomes the propelling power. As a crank 6in. in depth is quite sufficient for working the foot, so a driving wheel more than 36in, will be too great a leverage for that crank; and what is gained by a larger wheel down an incline is lost with more when on a bad road or ascending a hill. Sit as close to the driving wheel as possible, that the pressure may be on it enough pressure on the guiding wheel to steady it is sufficient. Regulate the height of your seat according to the depth of your treadle, so that when you are on your seat, and your legs straightened down, the foot may just fairly reach the treadle when it is at its extreme downwards. I would use two connecting rods-one on each side. Let them be your treadles. pivot them to the crank of the driving wheel (the hind One), also to the crank through the frame between the treadles may work in unison-oue handle to guide wheels. Let each crank be of equal length that the with, another for the brake; also a projecting bit close by the brake handle to steady yourself with (this something from these suggestions. I think we may is for driving the hind wheel). Perhaps you may glean more than 20 years, and I consider as yet it has been altered and not improved. The bicycle is fit for none but those who are fond of dangerous sports. Driving the front wheel of a tricycle, sitting so far from it, and dragging two behind, it is a mistake. Driving by levers pivoted near the front wheel is a mistake. A four-wheeled veloce is the best.-N. G. LAMBORNE. [2195.]-SMOKELESS LAMPS.-I beg to inform Practical" that the cone must be made to fit the reach up to that part of the wick just going to burn, leaving an air passage at top abou: free, as shown in my section, page 459. It must, moreover, be adjusted to each lamp so as to produce the best effect. The ball should be about the diameter of the round wick, also adjustable as to height for best effect. Hollow [2178]-CIRCULAR DISC-If "Indagator"! will balls of brass or iron may be got of the proper size at inscribe a square in a circle of the diameter of the oriary metal shop. The cone prevents the air passing fice-viz., ift, the side of the square will be the through the pierced bottom of the gallery getting into diameter of the required discs = 84853in. Or, if he the glass globe, and must not therefore be pierced. will square the diameter of the orifice, 12in. x 12in = For raising and lowering the wick, Practical" must 144; take half the product 72in., extract its square look at any well make round wick colza lamp, or, root = 8-4853in, because the areas of circles are to each argand burner. Upon the whole, as "Practical" does other as the squares of their diameter.-S. B.

[2220.]-SOLDERING.-File the end of the iron pipe bright, then see that the soldering iron (which should be as large a one as can be got, so that it may carry a great amount of heat) is well tinned; this is important in all soldering operations. When the iron has been in use some time after tinning, or when it has been made too hot, the solder and the copper become melted together and the solder seems to eat holes in the copper. In this state the iron is not fit for use, but must be Having the iron filed down smooth and re-tinned. ready, and as hot as it will bear, take and wet the part to be tinned with a little spirits of salt that has had as much zinc chippings put in it as it will dissolve, then apply the solder with the iron, bearing in mind that the pipe will have to be very hot with the iron before it will tin; it would be as well to tin the iron pipe with a little block tin or pewter, if available. If any difficulty is found in tinning the iron pipe a little powdered salammoniac might be sprinkled over it when very hot, which would assist the tinning; this done, the lead pipe must be widened out so as to form a lip all round the iron pipe, and soldered round with fine solder,taking care to keep the heat of the iron on the iron pipe rather than the lead, or what is called a plumber's joint may be made by pouring on a quantity of plumbers' solder from a ladle, and wiping off the superfluous solder with a greased cloth. For an SIGISMUND. amateur the first plan will be the most simple.

coloured copper coins are quite worthless.--HENRY yet improve the veloce. I have been a velocipedist reason why it should not be put in feed cistern and

(2170)-UNANSWERED QUERY.-Dissolve small quantity of corrosive sublimate in vinegar; dip or place copper coins therein; wipe dry, and finish with blacklead, using common stove brush.-W. H. 2176-BLAST FAN.-The proportions I sent "Fan Blast" (p. 563, Vol. X.) are suitable for a smith's forge. Let "C. T." look at them, and if he cannot get

[2224]-BOILER.-In reply to inquiries from "One in a Fix" respecting the use of Carrigeen moss to prevent the incrustation of boilers, I was recommended to use it by an inspector of boilers. I do not see any drawn directly to boiler, provided there is no overflow from cistern that would carry off the moss as waste. The quantity I would recommend for 50-horse boiler would be a stone weight per week (the present cost of the moss is about £10 per ton here in Ireland). I can not speak of its merits as a purgative of a very foul boiler, as I never allow a scale to get on mine; but I do think from using it that it prevents the formation, and I am certain that it is a very harmless article.

on with them I shall be very glad to help him all that lamp; that is to say, it is to stand upon the gallery and VIVIS SPERANDUM.

I can.-JOHN W. BEDFORD.

[21781-CIRCULAR DISC-Areas of circles vary as the squares of their radii: as, therefore, 36 is the square of 6in. (the radius of the given circle), the radius of the disc which is to cover half the area must be the square root of 18, or 4-2426407in.-J. B.

[2180.)-ENGINEERING IN GERMANY.-There are several engineering colleges - Polytechnische Schulen-on the Continent that have attained a world

not seem to be well acquainted with this subject, I
should advise him to apply to a practical lamp manu-
HENRY W. REVELEY, Reading.
facturer who will at once understand my section.-

[2225.]-VACUUM IN CYLINDER.-The exhaust steam leaving high pressure cylinder causes no vacuum, but, on the contrary, should the passage be too small it often causes back prefsure and compression on the return stroke by not fully and easily exhausting.-H. SUMNER.

[2227.]-LIFE PRESERVERS.-The life preservers found on all sea-going vessels are composed of slices of cork, neatly arranged and compressed together so as to form a zone 30 in diameter, 6" in width, and 4" in thickness; it contains about 12lb. of cork, is generally covered with painted canvas, and will support 6 persons. Inflated belts are liable to get punctured, and so tendered useless.-VIVIS SPERANDUM. [2227.)-LIFE-BELT.-" Avalonensis" would find made by the "Aquatic "the buoyant waistcoat Safety Company "better for boating than any of the and most portable things of the kind yet out.W. H. I. P.

"

wide fame. In these colleges very little knowledge to 8-horse would be about the power required for the ordinary life belts. My friends say they are the best

[2228.]-ADDRESSES WANTED. If "Foreign "Mineral Statistics of Correspondent" will get the Great Britain and Ireland," by Robert Hunt, F.R.S., published by Longmans, Green, Reader, and Dyer, and by Stanford, Charing-cross, price 2s., he will find the name of every colliery in the United Kingdom and where situated, and owner's name, besides a quantity of other useful information.-S. W. T.

of mathematics is required to pass the examination
[2200.]-STEAM LAUNCH.-An engine working up
in the preliminary course-Vorschule-and in four
boat mentioned by "Soliciter." I should recommend a
or ve years' study the student can have gone through vertical boiler for two reasons. Firstly, they are much
the various branches of engineering, theoretically and more convenient to get at for cleaning and repairs—a
anatically, the latter shown by excursions, if steady most important point where salt water only is used;
and diligent. Age required, 17; and yearly school fee, and, secondly, the tubes are not so likely to be un-
Karlsstablishments of this kind exist in Berlin, covered by the water in consequence of the pitching of
Karlsruhe, Hanover, Munich, Stuttgart, Vienna, the boat in a rough sea.
The boiler should be made of
Zurich, &c. Should any young
the best material and capable of standing at least 80lb.
the idea of studying there, I can gentleman entertain working pressure. The engines should have double
information. Lastly, the x area of the sector is =
cylinders and be fitted with reversing gear. Is not 9ft.
Manchester.
150 square feet.-A. TOLHAUSEN, 18, Waterloo-road, beam rather to much for a boat only 36ft. long?
About 7ft., I should say, would be a better proposition.
any further in-
(2182)-CONSTRUCTING COILS." Nemo" will I shall be happy to give "Solicitor"
for a coil the size he purposes making it would
require about 40 yards of No. 16 primary wire; but formation should he require it.-CANON.
[2204.]-PROBLEM.-If "W. B. S." considers h is
to theter to use No. 12. The number of sheets or wil problem, he will see that it resolves itself into finding
thebe pound of course depends upon its thickness: the height of a cylinder of water weighing 25 lb., and
the best foil, however, runs about 60 sheets Ift. square standing on a circular base 12in. diameter. I think he
to the pound. If the coil is well constructed the maxi-
can work this. With regard to his second question
mum spark will be about 6in. long. The number of (2205), the atmospheric pressure per inch which sus-
bottle batteries requsite will depend on the surface of tains 30in. of mercury in the barometer is the weight
carbon exposed: he will probably require five face of of 30 cubic inches of mercury, a table of specific
The secondary wire should be first covered gravities will inform him that a cubic foot of mercury
with silk and have some insulating material, in a fluid weighs about 136000z. From this he can calculate the
state, brushed over each layer as it is wound on the pressure required.-PNEUMA.
coil. Thin paper saturated with paraffin wax may be
substituted for gutta-percha tissue. The silk used for
[2208.]-CERAMIC MANUFACTURE.-The treatise
-H. B. MILLER.
on porcelain in Lardner's "Cyclopædia," which may
covering wire differs from ordinary silk in not being generally be bought at bookstalls for about 28. 6d.
contains an account of the colours used in painting
[2183.1- TAXIDERMY.
Taxidermist's and printing. There are several editions of Brong-
Manual," &c., by Capt. Thomas Brown, F. L.S., pub- niart, but no cheap one. The way I pick up my books
lished by A. Fullarton and Co., London. Price 38. 6d.
at a low price is by reading the catalogues of dealers
?).-WILLING.
in secondhand books, or sale catalogues; although I

twisted.-J. D. M.

The

[2233.]-STAINED GLASS.-A small treatise on "Glass" is contained in Vol. 115 of Lardner's "Cabinet Cyclopædia :" after this, study the works of the late Charles Winston, to whom every glass painter is deeply indebted for the untiring attention bestowed on this art, from 1830 until his lamented death in 1864. They priucipally consist of "An Introduction to the Study of Painted Glass, with Remarks on Modern Glass Painting." 1849, Parker; "Memoirs Illustrative of the Art of Glass Painting," 1865, Murray; "An Inquiry into the Difference of Style Observable in Ancient Glass Paintings, especially in England, with Hints on Glass Painting," 2ud edition, 2 parts, 1867, Parker and Co. "Proba est materia, si probum adhibeas artificem."Erasmus. I trust this reply may not prevent Mr. Leicester from rendering his highly-valued assistance. [2234.]-FROM "JUPITER."-My 3in. glass was got from S. and B. Solomon's, 39, Albemarle-street, London; price, on pillar and claw-stand, £5. It has one day eyepiece about 40 power, and one night-power 100, but I have added several others since-20, 60, 75, The latter works very (100 day eye piece), 150 and 275.

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