has a draw box, and a draught of about 2, then he can handle it pretty strong, as the fibres are already straightened ready for drawing. But if he has no draw-box to his engine, or only one with a draught of say 1-25, if he will examine the sliver, he will find the fibres all ways, and it will be seen that under the above circumstances it would be foolishness to subject it at once to a great draught, therefore it should be "coaxed" straight. Under these circumstances, "Factory Lad" will find the following the best distribution of his draught:-Between back and 3rd, 125; between 3rd and 2nd, 1.87; and between 2nd and front 3; total, 6-99.

B. W.." Rochdale, talks about a draught between lap and feed rollers. Now there is not-or rather, ought not to be-any draught at all there. What use would it be? The lap should be delivered just as the feed rollers want it, neither slower nor faster. "B. W." must bear in mind there is no draught between the doffer and delivering rollers, but a contraction. HARMONIOUS COTTON SPINNER.

"Core

SIR, I have read a letter on Roving B. W. R." says it is immanterial whether the bobbin leads the flyer, or the flyer Frames." in April 22. leads the bobbin; if that be true, I should like to know the object of the frames being made to gear in that to a Mr. E. Slater, April 29, page 133, if there be no form, which appears to be the general rule according advantage in the make of the thread by running the bobbin quicker than the flyer In my opinion it is a disadvantage to the wear and tear of the machines, besides taking more power to run the bobbin 11 to 1, than would be required to run it 9 to 1 of the roller. My reason for seeking information is because I have been a worker of cone frames 10 or 12 years. In Taylor Wordsworth's make for worsted, the gearing is 80 arranged that the flyer must lead the bobbin. Multiply the diameter of delivering roller by the revolutions per minute; for a dividend divide by the diameter of bobbin, the quotient subtracted from the speed of spindles per minute will give the number of revolutions the bobbin will make per minute. Since I read B. W. R.'s" remarks, thinking there was something in the make of the thread, I tried to run the bobbin quicker than the flyer, but on account of the gear I could not. E. HALMSHAW, Gomersal.

What is meant

it, and the back and front wheels must both make an
equal number of turns in a given time, because they
have both the same number of teeth.
is the time you might fix upon if
by "a given time
you were making an experiment, as one minute, two
minutes, or any time you please. Let us now sup-
pose these rollers are making 40 revolutions per
minute, how much farther will the surface of the
front one have travelled than that of the back one?
If we multiply the diam. of a circle by 3'14, we shall
get as near the circumference of it as we require for
our purposes, and the circumference of a circle is the
distance it would travel if turned once round. Then

lin. diam. of back roller, x 314 = 314in circum., and
314 x 40, the number of turns = 125-60in., the dis-
tance travelled by the surface of back roller, and con-
sequently the length of yarn it would take in during
a minute; and 2in. diam. of front roller × 3:14 =
6-28in., its circumference the same as before, 6:28 x 40
=251 20in., the distance travelled by the front one.
Now if we divide the latter distance by the former,
we evidently get the dranght, as 25120 125 60 2,
the draught of the rollers. They would draw out lia.
This example shows us that the draught is
into 2in.'
the result of surface speed, and not of speed of revolu-
tion, as both the rollers make the same number of
turns, that is 40. Again, the circumference of a
circle is always in proportion to its diameter, so that
simply dividing the diameter of the frout roller by
in this case we could have found the draught by
that of the back one, seeing they have a similar speed
You will observe also,
of revolution, as 21 = 2.
that the draught must not be called the difference in
the speeds, although it is the result of such difference,
because the difference between 1 and 2 = 1, as 2-1
= 1, or 10 - 55; but if one travelled 10in. while
the other travelled 5, the draught they would cause
would be 1052, and not 5, which is the difference
between 10 and 5. And further, suppose you wish to
draw out 5 hanks into 50 hanks, the draught required
You may call
would be 505 10, not 50-5= 45.
it the geometrical ratio between the two travelling
speeds, its measure being the quotient obtained by
dividing the greater by the lesser. In a future letter,
I will endeavour to make you understand the matter
entirely. Perhaps some may think that I am treating
the subject in too simple a method; if so, I am not
writing for such as they, but for the lads, and I know
from experience that, to them, the more simply I
speak, the more useful the information. There are
hundreds and thousands of factory lads, adults if you
will, who, like myself, have not had the opportunity of
attending a school, or at most, only for a few months
at the time, when they were too young to learn any-
thing that required study, or the action of reasoning
powers, and what may such as these do but pick up
aud scratch off information from any thing they can?
If the thing has too much weight in it, they cannot
pick it up, and if it be too hard, they can scratch
nothing off. The ENGLISH MECHANIC is doing a
marvellous work, and judging from the common sense
views of its Editor, and the many gentlemen who con-
tribute to it, it must go on working in the future until
it comes to be looked upon as one of the little begin-
nings that has been developed for a good purpose, and
carried out to a great end. The enterprise itself is the
fulcrum, its pages are the lever, and all who will
may take hold and sway down as much as they can,
until we are raised up from a state of chaotic igno-
rance, to one of scientific knowledge. If now, some of
the kindly F.R.A.S's, who have such great strong
hands, instead of being generous and courteous, were
to be thoughtless, and if, when they put their hands
upon the lever, they crush and bruise the fingers of
their less gifted brethren, so much that they made
them tired of the good work, how unfortunate would
be the result, and how contracted would be the sphere
of its usefulness! Let the MECHANIC, then, come to us
23
top
like the sunshine, tempered so that the light it diffuses
may be gladness in the high places, and health with
happiness in the lowly ones.

SIR,-If I am not mistaken. "Mutual Improvement," page 111, intended the question propounded by him to be somewhat ambiguous, as the rule he quotes cannot be strictly correct," because it takes note of no draught in the carding engine, save that between the "feed rollers" and "doffer," although there are two other draughts outside it; so that obviously, the draught of the engine must be the total of the three. The first draught is between "lap roller" and "feed rollers;" the second between "feed rollers" and "doffer" (for finding this one the rule is correct); the third, between "doffer" and "calenders." There formerly was a "draw box" attached to each carding engine, for the purpose of adding to the draught of the engine a considerable amount-some have them still, because they are "penny wise and pound foolish." It may also be said of the draught of any machine, the theoretical draught is not often the working one, as the latter depends upon the qualities of the cotton, and varies accordingly. A word now for the lads on the subject of draughts. The term, as used in cotton spinning, means the drawing out, into greater length, of the fibrous bands of cotton, by the rollers through which they pass in the process of manufacture. The cause of this drawing out, or draught, is the accelerated surface speed that is given to each "line" or "row" of rollers in a set, from back to front. Now, as you know, the

and "bottom rollers seize the cotton between their surfaces as they revolve, and draw it forward at the same rate of speed as they themselves are travelling, the back ones taking it in, or "feeding," and the front ones sending it out, or "delivering "it. If, then, we wish to find out how much longer the yarn, or sliver, is being made by any set of rollers through which it is passing, or, in other words, if we wish to find the draught of the rollers, we have only to find out how much faster the surface of the front one is travelling than that of the back one, by dividing the speed of the quickest by that of the slowest, and the quotient is the draught. Look now at the sketch, take the back roller to be lin. diam., and the front one to be 2in.; as the front roller generally drives all the rest, you must take it to have a wheel on the end of it with 20 teeth, this drives a carrier of 90 teeth, which communicates its motion to the back roller wheel, with 20 like the front one. It will be evident to you, that although the carrier has 90 teeth, it cannot give any greater or less speed to the back roller than the speed of the front one, because it transmits its given motion from the same diameter it receives

Edward Habergham seems to have had an idea that the anomaly he speaks of is not anomalous-no more it is. The avoirdupois pound contains 7,000gr., and in weighing cotton, 24gr. make 1 dwt., but 20 dwts. do not make 1oz. He was mistaken, I think, when he said we are told so-4374gr. =1oz., and 437 x 16 = 7000. Have you been trying to work Egyptian" and "Surat" together, Edward, or avoirdupois and troy, eh? LetFactory Lad" page 136, divide his 7 by 3, and make the draughts of each line of rollers in the drawing boxes equal, as 24 + 2 + 24 = 7, or 24+ 2} + 2} = 7. If he is working "middling American" cotton, and "putting up" six ends, let him, if he can, reduce the total to 6, and get his rollers as near together as he can, unless their diameter be no more than the length of the staple.

E. SLATER, Burnley.

p.

SIR, The question asked by a "Factory Lad"
136, on the proportionate draughts in a drawing frame
with four lines of rollers, is one on which he will find
much diversity of opinion to exist amongst practical
cotton spinners. I willingly give my opinion, and
hope others will do the same, although I know that in
first-class concerns, where different systems prevail,
particulars of this sort are generally regarded of some
importance, and as secrets belonging to the business,
not to be divulged to rival spinners. Whatever scru-
ples there may be as to furnishing information of this
sort between individual firms, with a publication such
as the MECHANIC, such scruples are inadmissible, and
may be disregarded.

For a medium-stapled cotton, I should place the
draughts as follows:-

Between Front & 2nd rollers 2nd & 3rd 3rd & back
Draught
1.92 X

2:65

1:38

To keep the ball rolling I should like to see opinions pro and con., on an up or down draught in a scutcher. B. W. R.

DARK LINES IN SOLAR SPECTRUM. SIR, -In reply to Mr. Proctor, I cannot give any evidence based on my own observations of the dark lines in the spectrum, not possessing instrumental means for taking them. If he does, I fancy the question of their origin can be determined in this way. Suppose such a day as that described in my letter on p. 658, Vol. X., is selected for an examination, commencing with the sun on the meridian. If the dark lines are broad and clear, and they diminish as the sun descends to the horizon, we may safely refer them to solar absorption. If, on the contrary, they are narrow and indistinct, but widen out with the descent of the suu, then their terrestrial origin is plainly shown.

T. A.

["T. A." says he cannot give any evidence "based on his own observations." Does he not know that observation of phenomena is the initiatory step in scientific investigation? Why go on guessing and IfT. A." would supposing, without observing? observe first and infer afterwards-record facts, and then generalise, it would be better for him and others. A man like "T. A." may go on speculating on “ifs," and fancying questions for a lifetime, and still be no wiser. For thousands of years, up to the time of Bacon, men-and great men too-proceeded as "T. A." does. And what did they do? Certainly not much. We tions, and Science would be nothing but a chaotic nean nothing offensive when we state a million of men might pursue "T. A.'s" method for scores of generaguess.-ED. E. M.]

DRILL FOR DRILLING STONE AND BRICK. SIR, I have sent you a rough sketch of a drill which I have used for drilling stone and brick; it is an

arın which you hold with one hand to turn the drill
whilst you strike with a hammer in the other.
A COUNTRY LAD.

PLUMBAGO v. PLATINA BATTERIES. SIR,-In your last, T. S. Conisbee refers to the use of plumbago in the place of platina as an aliment and containing cell for the nitric acid battery. I hope for the good of all of us interested, you will find space for my opinion on the merits of plumbago and platina. About 1813 I was experimenting upon the power of various forms of batteries, both platina and carbon, and then discovered that the plumbago could be made the porous cell for holding the acid. I had several forms of them made, round and flat, which gave great power for hours, a description of which was given in the Practical Mechanic and Engineer's Magazine, Vols. II. and III. The only difference between my arrangements and the newly-invented one is the putting the stopper upon the old invention, thereby increasing its defects. After years of experience, I am in a position to state what can be got from plumbago or platina. First, plumbago, charcoal, or gas coke, all of which have been found to give a powerful current in contact with strong nitric acid, are by far the cheapest to get up, and work well for some time; but, unfortunately, they get filled in their pores with a glut, get detached from their connections, or crumble down after drying, requiring frequent renewal and repair. Now, as to platina, the first cost is somewhat additional, but if often used it soon proves the cheapest. And here I would advise all who wish to have a good powerful battery not to use the thinnest platina foil; get it somewhat stout; make the connections a short distance from the fluid with platina, coat well with shellac, use the strongest nitric acid, saturated salt and water with the zinc porous tube, soft pipeclay, wood, or vegetable parchment, and you have the simplest and most powerful arrangement yet known. A. FARQUHAR.

THE BEDFORD CANAL EXPERIMENT-SIX
MILES.

SIQ. As a correspondent has asked for some particulars respecting the above, I, having read all the correspondence, and tested the experiment on paper, will, with your permission, reply. In the first place, I may state that the flat theorists cannot seem to comprehend the laws of gravitation and the rule of tangents, together with the laws of perspective. The first experiment consisted of sighting from end to end with a 5-foot telescope, the line of sight forming a tangent with its centre in contact (to a sphere), the centre signal appeared approximately over 5ft. above it, thus proving that the three points were not in a straight line, but that by adding refraction, making 6ft., a curve with the radius of the earth would intersect the three points. The diagram of this experiment was signed under protest by the globular opposer's referee, for what reason would appear strange to us who know the rule of three "boring sticks." The next experiment consisted of sighting from end to end with a Troughton's level, the line of sight (in this case) forming a tangent with its point of contact at the first station. The centre signal (if reversed) appeared below the cross hair, and the end signal below the centre one; thus proving that they were not in a straight line, but dipping from the tangent.

This experiment was reversed at each end, with the same result. But the globular opponent's referee argues that as the two signals and cross hair appeared equidistant from each other in the telescope, for that reason they must be in a straight line from end to end, and that the apparent dipping must be the result of perspective diminution; but those of us who know anything of the laws of perspective could inform him that all objects standing upon a straight plane with their tops the same height as the eye, must line with and cut each other, and that the bases only will vanish Towards a horizontal line passing through the eye. If the signals and cross hairs were equidistant, it would prove curvature; to wit, if the end signal dipped (less refraction) 20 ft., the centre one would dip 7ft. 8in. By making a side view on paper it will be tound to be a curve (horizontal scale, say lin. to a mile, vertical, fin. to a foot).

The problem may also be tested perspectively by measuring the dips on the vertical picture line. But as this curve does not give the theoretical value-viz., 5-14ft. in 3 miles and 20 57ft. in 6 miles (refraction deducted), as partly proved in first experiment, we have good reasons for doubting this equidistance. For the theoretical curvature the centre and end signals should appear twice as far apart as the centre signal and cross hair-as may be tried by a perspective problem. In the diagrams of Mr. Wallace's referee they are shown about in that proportion, but as all the diagrams seem to have been rough sketches, they must be taken approximately, otherwise a micrometer should have been used. A curvature has been proved, therefore, on Mr. Wallace's side, although doubted by the opposite side. We may also consider it (in the absence of minute measurement) as the theoretical value, viz. :

sighting 514+ refraction 86 = 6ft. in 3 miles. sighting 20:57 + refraction 343 24ft. in 6 miles. The diagram represents a geometrical side view of the combined experiment, with refraction lessening the actual dip. E. Y. POOLE, Grovetown, Weston-super-Mare.

FACTS WANTED.

SIR,-I confess to being somewhat sceptical about the astounding theory put forth by Mr. Henry W. Reveley, of Reading (No. 266), respecting speed and power in locomotive vehicles. If I understand his assertion rightly, he states that the higher the rate of speed at which a vehicle is driven, the smaller will be the amount of power required. If such a theory could be substantiated in practice, it would certainly be a grand thing for we poor velocipedists, who are held down to something like eight miles an hour, by those mortal enemies to progression, gravity and friction. If the statement be true, that the higher the speed 18 such a thing as a speed so high, that no power the smaller the power required, it follows that there would be required at all. And having got thus far, might it not be possible to coax our vehicle to put on a little additional speed, and so create a little surplus power to be applied to some praiseworthy object, such as grinding the coffee or churning the milk (vide Punch), while we were taking a short canter, (50 or 60 miles) on our velocifere, before breakfast. I have read Mr. Reveley's epistle with much interest, and will become a convert to his doctrine when he brings one or two facts of vehicles of any description ever having been driven with less power at a high speed

than a slow one.

J. HASTINGS.

SCREW IN CHUCK-TO "HEATHEN JACK." SIR,-If you study "A. B.'s" drawing you will see that what you suppose to be a left hand screw is a right hand female screw shown in section, and, therefore, has the lines representing the thread, slanting the same way as an outside male thread. As to the other point, you misquote my letier by leaving out the words "of the mandrel," after" each end." I meant that the mandrel is double ended, and carries a chuck on each end'at the same time, which necessitates One being screwed right hand and the other left. Lastly, it is by no means uncommon to find right hand screws inside the cylinders of back centres, and many prefer it, as it renders forcing up a drill easier work, owing to the workmen only having to lay hold of the fly wheel on the screw, and keep pulling. So I don't think it wrong altogether.

J. K. P.

JUMPING FROM THE TRAIN. SIR,-In reference to your correspondent's view on the subject of "Jumping from the Train," will you permit me to suggest what I think is a somewhat different view on this subject, but one that appears to me the correct one, and one that, I believe, has stood the test of experience with guards and persons in a position to need the jump for safety when a train has been proceeding with great velocity. It is to throw yourself with backward jump slightly inclining the contrary way to the direction of the train. Of course it will easily be seen that when the feet reach the ground their motion will be arrested, but the rest of the body will fall violently in the direction taken by the train. If the jumper jump face forwards away from the engine, he will come violently on the back of hi head; if h jump be, as I state it should be, his fall will be on his face. but he will have his hands

3 MILES.

BRIDCE

ready to break his fall. If his jump be with the train,
forwards, he will add his own velocity to that of the
train, which needs no addition. The ordinary idea is
to jump forward in the train's direction; this will
answer, and is the only way when the jump is from a
carriage drawn by a horse; but when the velocity is
that of steam, 30 or 40 miles an hour, the action must
be different.

A very active little station master, well known to
those who frequented Leicester station 12 or 14 years
ago (Mr. Tyers) is, I believe, my authority for this
view, and it was more than once tested by his expe-
rience. I trust, however, neither I nor any of your
readers may ever be in a position to require to try any
method of leaving a train, but should it be our lot,
there appears to be more philosophy in this one than
in any other.
O. W. W. G.

THE SALTAIRE-WARDOUR STREET LATHE.
Flat's" letter, p. 162, whether he asks for informa-
SIR,-I am not quite able to make out "Natural
tion in good faith, or to rile me by saying I state more
than I can prove, or to defend the writer of the article
which appeared with the drawing, or to make me
commit myself to some further statement that cannot
be borne out, with the notion that what I have already
written is actionable somehow, only that I am not deep
enough in the mud yet. He is enough at home at Mr.
Smith's and Mr. Salt's to be able to compare their two
lathes, and to promise specimens from-it is not
quite clear which. So he can't be at a loss for infor-

mation.

made to Mr. Smith's design, and had to be altered to make it act. The present fly-wheel is not the one which came up at first, though of the same pattern. I have already spoken of the overhead motion, and see no reason to alter my opinion.

As Mr. Evans's account amounted to some £1200, it is pretty clear either that the lathe was made by him, or else that he had a very large sum of money paid him for not making it. J. K. P.

COMMERCE AND TRADE.

Sta

SIR.-Many fallacious idens are based on such figures as those quoted by "Saul Rymea," p. 161. tistics are perfect edge tools, and want careful handling, while they can be made to do almost anything. It has been no uncommon thing for even statesmen to cry out because imports exceeded exports in value, we should be in a bad way if they did not do so. The difference on the totals, if these could be really ascertained, which is a thing impossible, would represent the cost of carriage, or shipping, and our profit. Would a man of business think himself well off if his sales, or exports, exceeded in value his returns, or imports? Well, the same holds good of the nation's commerce. Further, it is said, "But we have to pay the difference in gold"; be it so. Is the gold we receive or the bills of exchange, included in the imports? Australia sends us millions yearly in exchange for goods which count in the exports. Then it must be remembered, England is the banker of the world, her business accounts cannot be balanced at one point, they include those of too many branch houses; her profits can only be ascertained in connection with the operations of the whole empire, nay, the world. Meanwhile, her material wealth is vastly accumulating, and being capitalised in the form of railroads, a commercial navy, such as no other nation, or all other nations together, cannot approach; in constantly increasing loans to foreign nations; in works erected all over the world by her money, and bringing to her an annual return. These 1acts are much better evidence of the balance of profit of England's trade than any deductions from very imperfect and little-understood figures.

CHEMISTRY.

SIGMA.

SIR,-Lately some articles on various points in chemistry, have appeared in your columns, doubtlessly as cleverly written as usual, although, as a rule, they are more or less superficial; still, though they may be useful as showing their authors' views, they are seldom so for much else, being usually very elementary, are not necessarily the generally received views, and do not often exhibit more than one of the many sides to a question.

Those of your readers who wish for a thoroughly reliable and scientific dissertation on the question of atoms," &c., had better refer to the "Journal of the Chemical Society" for September, October, December. &c. Despite the fine defence of the "atomic theory." or rather of the single branch of it, it would appear to be doomed as admitting of no proof at present, though it is probable, nay, very probable; therefore we must regard as certain, that the branch of the atomic theory containing the assumption of "fixed material indivisible atoms," will gradually be abandoned. But it must be remembered that the assumption of the existence of these, we may term them, "materialistic atoms," as was well pointed out at the meetings of the Chemical Society, is not necessary to the Atomic Theory," and Dr. Williamson did not even attempt decisively proved by Stas to be correct. to prove the existence of them. No, the atomic theory is based on a much firmer foundation, that of "chemical equivalentism," which has been so

Notation," an attempt to defend the system of symbolic Nature has a paper by Dr. Olding, on " Chemical equivalent notation on a basis apart from the theory of Dalton's materialistic atoms, which he, along with many of our most distinguished chemists, abandons. Though it will fulfil its purpose, it is not a very good definite equivalents, which has not been challenged, correct. It is, however, unnecessary: the theory of defence, though coming from Dr. Olding, of course and on which his own defence rests, is of itself the best and most complete defence of our system of equivalen: notation. Neither is the paper in Dr. Olding's usual brilliant and conclusive style, and is not so forcible as would be expected from its distinguished author.

The views originated by Professors Wanklyn and Williamson, radically modified and amended, it is true. are gradually spreading, and give hope that the mist so long persistently enveloping the questions of valency, radicalism, &c., is at length being dispersed. They are, it is true, still in great confusion, and very rough, but this disorganisation is due to the magnitude of the work, and they are gradually being brought into better condition. Undoubtedly it will prove a laborious task to reduce all to a proper system, and all parts may require great revision and amendment. When it is finished, and that I hope before long, we shall have the questions of valency, di-, quanti-, and multi-valency; radicalism, and di-radicalism, polyatomicy, and poly-equivalency, with the innumerable other analogous points, brought into an intelligible form; at present, it is some years' work to even properly comprehend their meaning, much less to understand them.

Now as to my statement-which I should have been a born fool to make if I did not know what the facts are. I said a "great part" was rejected. Now I might defend the expression by saying that a purely ornamental lathe does not of necessity involve either bed, standards, fly-wheel, crauk, treadle, or poppet-head, so long as there is a mandrel with means of driving it either by hand or power, and a slide-rest; but this lathe is equal to a little more than marking crooked lines with pencil on paper, which is about as much as many an expensive geometric chuck can do, and there."Sigma," have noticed the letter in Nature, of Doubtless the "Harmonious Blacksmith" and fore ir estimating the "great part," we must take bed, April 14th, on the dinernis. Lately, there has been standards, &c., into account. Now the lathe, when it two papers read before the Zoological Society on the came from Yorkshire, consisted of-firstly, one bed same subject. fitted to; secondly and fourthly, one mandrel-head fitted with mandrel and saponifying almond oil, decomposing the soap formed thirdly, two standards; Oleic acid (Experiment No. 2617), is obtained by pulley fifthly, one poppet-head; sixthly, one fly-by an acid, and converting the fatty acids into their wheel fitted to; seventhly, one double-throw crank. lead salts by means of oxide of lead. The plumbic There was no treadle to it. The rejections werefirstly, one mandrel-head with mandrel and pulley hydrochloric acid, the etherial solution decanted, and oleate is dissolved out by ether, and decomposed by fitted; secondly, one fly-wheel fitted to; thirdly, one the ether distilled off, leaving nearly pure oleic acid. double-throw crank: these parts were remade. The It can be purified by converting it into its baryta salt; leading screw, saddle, and everything else except the treat with alcohol, and decompose with sulphuric acid. poppet-head, which I have since heard was altered Glycerine is obtained by saponifying any neutral fat, Evans. The saddle to carry the slide-rest was first to correct the fault I pointed out, were made by Mr. and is a secondary produce of the soap works.

Oculus" (No. 2608), will find that the irritation of

the skin caused by sulphate of atropia, can generally be prevented by first adding a little alcohol to it. M. Brandau gives, in his paper on chlorous acid, in the Aunerlen der Chemie und Pharmacie," a new method of preparing baric chlorate, which I find to be pretty good. He obtains the salt by digesting well a mixture of sulphuric acid, water, aluminic sulphate, and potassic chlorate, dissolves out with dilute alcohol the chloric acid, neutralises with barie hydrate, and then, distilling off the alcohol, crystallises out the baric chlorate. It yields a salt containing 993 per cent. of baric chlorate.

I note the letter of Mr. Edward Richards, in your paper, on page 137, in which he fully details his method of obtaining the percentage of sulphur in iron, by the nitrohydrochloric process. I do not consider the process itself the best, but the system of manipulation is very good, although, for strict accuracy. I prefer a few alterations in it, which I use when adopting it, though I generally use either Rammelsberg's or Mitscherlich's method in preference. For instance, the presence of a little chromic acid during the oxidisation of the sulphur is often an advantage, as effectually rendering the conversion of all the sulphur into sulphuric acid certain, and preventing any fumes of sulphurous or chlorosulphuric acids, while it does not interfere with the after reactions. Likewise, the neutralisation of any free acid (nitric or hydrochloric) is advisable before precipitating the baric sulphate, as they greatly increase its solubility, so if it is not done, and the proportion of sulphur is large, it is advisable to use the acetate instead of the chloride of barium. Even if it is done, it is as well to use the nitrate in preference to the chloride of barium, as it is almost impossible to wash out all the chloride by water alone, from the precipitate of sulphate.

These precautions may appear trivial and unim- lathe, of which I forward a photograph. The uncovered portant, and perhaps, for rough practical work, where wire is wound on the large reel at the back of the only a certain degree of accuracy is needed, are so. lathe; from thence it passes over the small pulley For exact accuracy, such as is essential for reliable attached to the lathe itself through the hollow mandrel, scientific work, though, they can not be safely dis- which has fixed to it the reel or reels of cotton for regarded, as otherwise, as I have known, the sulphar covering. As the wire is covered it is wound on the may be considerably under-estimated. The effect reel, which is supported by the rest socket. The wire their neglect may cause is seen if we remember that passes through the base of the winding-off apparatus, a small trace of nitric acid will raise the solubility of the reel of which has fixed to it a handle and click wheel. baric sulphate from 3 to 30 millegrammes a litre, while To the reel on which is the uncovered wire, a small pulley a little hydrochloric acid will more than double this; so is fixed at the outside, over which a cord passes with a nuch so, that sulphate of baryta precipitated by sul-weight attached to make it friction tight. This, then phuric acid from the chloride, will often have 10 per is the description of the machine. The other parts, cent. held in solution by the hydrochloric acid; in-shown in the photograph are those of the rose engine. deed, I have known as much as 180 to 220 millegram- Of course the machine may be made self-acting by mes per gramme thus dissolved. Kirwan ( Ann. Chem. driving the winding-off reel from the overhead motion. Phys."), and Calvert (" Phil. Mag.") well illustrate the need of precaution in estimating sulphuric acid, through the solubility of barie sulphate in dilute nitric and URBAN. hydrochloric acids.

TESTS.

SIR-I am glad to inform "F.R.A.S." that my 3in. refractor has separated Gamma Leonis, Epsilon Bootis. Delta Gemini; these are all the objects I have been able to try my telescope on, with the exception of Gamma Virginis. On turning my telescope on this star for the first time, I found it double with my highest power 96 times. Is this a favourable result? I should have tried more objects, bnt was prevented partly by light clouds and partly by the chimney-tops, which form a great part of the scenery from our doorstep. He will excuse my not sending better results, as when there has been a favourable evening I have been prevented from observation by engagements. I am much obliged for his replies to my queries in the ENGLISH MECHANIC of April 22. If Hugo" (2592) would place a piece of lime on the back of his small mirror it would keep it perfectly tree from moisture. This has been put into practice upon the plane of a 74 mirror, and gave satisfaction; but a better plan is to take the plane mirror out of the tube, and to place it, silver face down, on a piece of leather well rubbed with rouge.

W. BAGULEY.

JOE BARNES AND HIS YORKSHIRE SLAB.

SIR,-The other morning I called upon my friend, Joe Barnes, and found him busy making a refracting telescope. Although remembering his success with a 13in. reflector, ground and polished by the most simple means, I was not prepared for what he had now to show me. Having procured a square piece of Chance's camera flint-glass, he had set to work with four pieces of Yorkshire slab, rounded, ground, and polished his flint, added a piece of crown glass, and rounded, ground, and polished that, using no iron tool, not even a correcting tool, nothing but his four slabs, and making a pitch tool for polishing upon them. Being anxious to ascertain the results obtained, he had fitted the glasses into a square tube. This morning (Ap. 28)— the sun completely obscured by clouds-I could read the smallest type in your "Correspondence column," at a measured distance of 100 yards. The diameter of the object glass is 6in., and its focal length about 71t. 3in., but he says that the colour is yet under-corrected, and expects he shall have to make the combined focal length some few inches longer before the colour is properly corrected. As the construction of an achromatic telescope is always considered a matter of the greatest possible delicacy, and as men of the greatest experience, aided by the best adapted meaus, sometimes find themselves disappointed in the results of their labours, I think the above shows that much may be done by very simple means, and that if so much can be accomplished by a first attempt, we may expect he will ultimately succeed in his, to me, unheard of speculation. If you think any of your readers would be likely to imitate Joe Barnes, they will certainly feel gratified in reading the above, and should he ultimately succeed in making it to his mind, I will, on some future occasion, report.

PROGRESS.

WIRE FOR ELECTRO-MAGNETIC APPARATUS.
SIR,-Some time since an inquiry was made in the
ENGLISH MECHANIC for a description of a machine
for covering wire for electro-magnetic apparatus.
Many years ago I adopted such a machine to my own

N. S. HEINEKEN.

engine?

bottom, what contrivance is there for arresting its

When the ram has driven out all the tallow at the downward motion, and so preventing it driving out also the bottom of the cylinder? If the engineer is expected to be at hand to throw it out of gear at this particular juncture several times during the day, and to wind up the ram and refill the cylinder, I fear it would not get the attention it would require for its efficient working.

Wherein consists the patent right? as appliances of some time, with the apparatus, so far as quiring less attention on the part of the engineer, and costing considerably less.

a nature similar to this have been in on for

see, re

occupying too much of your space, to questions which It is difficult giving a satisfactory reply, without extend over so wide a field as that of "Excelsior's," (2648), on "the best carding engine at present in operation." Querists should state the class of work to which their questions apply as there is a wide difference in carding for Nos. 10s., and 100s.

REPLIES FROM “AN ADEPT." SIR, Although still an invalid, I must endeavour to reply to the various inquiries addressed to me by sever al correspondents. With respect to the query is the most advantageous as a pedal organ, but if the of G. M. Little, No. 2410, page 69, No. 263, a Bourdon progress he has made in building his instrument is not too far advanced, I should most earnestly recommend him to carry the principal, twelfth and fifteenth steps down to CC, or at all events to prepare the soundboard for their subsequent insertion, as I fear For medium numbers I think of no better system of he has no idea of the effect, of what he proposes to construct, will be, if carried out according to the de-carding than with rollers and clearers, properly set, and kept true, the stripping and grinding being scription he has given. regularly attended to at proper intervals. For finer and clearers, finisher engine with revolving flats and work, breakers and finishers, breakers with rollers self-stripping apparatus.

As your correspondent "Siddeley," on page 88, No. 264, asks my opinion upon his proposal to place two feet to, one valved pipe, I consider he would find that the advantage would not compensate for the additional complication, and I presume that he is aware that valved pipes in any form are not in favour in this country, on account of their great liability to derangement, inequality of tone, and general inefficiency.

I beg to refer "Simplex," page 188, No. 266, to the
commencement of my instructions on page 67, No. 211,

Vol. IX. In the first three or four communications he
will find, I trust, a pretty clear account of how to set
out his soundboard, and also full details of its con-
struction, which will include his other requirements,
only, if I may suggest to him, the substitution of a
dulciana, in place of the trumpet, in his specification
for the proposed instrument, I think he will find it
much more satisfactory.

In reply to W. J. Raybould, No. 2691, page 167, No.
267, the two articles he has described and figured are
concussion bellows," which are generally used in
large organs, simply to counteract, the evil effects of
clumsy or careless blowing.

AN ADEPT.

ON THE USELESSNESS OF OBJECT-LENSES
OF LARGE DIAMETERS FOR OPERA-
GLASSES.

SIR,-"F.R.A.S." appears to object to the reasoning
of my last letter with reference to this subject. He
must be aware that to give a power of two diameters
it is necessary that the eye-piece should be placed
half-way between the object-glass and its focus. In

-PUPIL

my last diagrams, the eye-lens was omitted; this,
can point out material flaws in my reasoning, I shall
however, did not affect the results. If "F.R.A.S."
be glad to set matters right.

The above remarks may serve as a hint as to the
uselessness of expending money for large lenses in
such cases.
S. T. PRESTON.

stickers to the pulley, one on cylinder and one on For the ordinary times of grinding I should prefer doffer, which are also worked from end to end of the engine by means of a spiral groove in the shaft," because at these times all that is necessary to be done is to brush the dirt out of the cards and to sharpen them up a little, which is done quicker with the sticker than the pulley.

When the emery rollers have been on for grinding pulley might be used for a short time to give better true the cylinder and doffer, previous to setting, the points to the card teeth.

B. W. R.

SUNFLOWER.-RUSHES.-STARCH, &c. SIR,-Having read with pleasure (p. 114, No. 265) an interesting note on the utility of the sunflower, I beg to add a few words to it. The seeds of the sunflower yield 15 to 16 per cent of oil. This oil is extracted in some parts of Italy and Germany; the refuse cake is employed as food for cattle. Samples of the oil, coming from Berlin, were exhibited last year at Amsterdam; the price quoted was, for the yellow, 15 thalers (458.) per 50kil.; the white, 163. It is said that this oil, being very cheap, is employed in many cooking operations instead of butter or salad oil.

Several other seeds of plants of the Composite order have a good produce of oil, for instance, niger seed, or Ram till (Guizotea oleifera) yields 35 per cent.; safflower (Carthamus tinctorius), 19 per cent.; Madia sativa, 32 per cent; Burdock (Arctium lappa) 19 per cent.

Another correspondent (p. 115) is quite right in considering rushes a good material for paper making effectively. Some years ago, Chevalier Claussen, at one of the meetings of the British Association for the Advancement of Science, said: "I found to my great satisfaction that the common rushes (Tuncus effusus, &c.), contain 40 per cent. of fibre, equal, if not superior, to the papyrus fibre, and a perfect substitute for rags in the manufacture of paper, and that a ton of rushes contains more fibre than two tons of flax straw." At Paris, in 1867, were exhibited several samples of paper made from Australian rushes, sent by Dr. F. Müller, Director of the Botanical Gardens at Melbourne; those rushes were principally Scirpus (Clubrush), Cyperus (Sedge or Gallingale), Heleocharis (Spikerush), Xerotes (dry rush).

We have had several very interesting articles on Starch; let me bring my "brick" also. A thousand pioneers are wanted to discover all the useful substances which remain unemployed in far distant countries. I beg to give the names of some exoti

He can easily find out if that is anything like the size of his channels.

"E. J. H.," No. 257, p. 589, 1829.--The springs of the harmonium-I mean the springs below the reservoir, if unequally made, sometimes causes the music to sound in waves. The expression valve in some instruments is placed on the top of the reserve boards, with one spring attached to keep it open; in such a case, if the valve is rather slim, and having a slight tendency to rise higher on one corner than the other, immediately you cease blowing, the wind issuing from the reservoir shakes the valve and thus produces the shaky sound complained of. It will be obvious that the same failing in a register valve would cause the same effect, but I have never met with such a case. The first two mentioned causes being the only ones I have had to cure. In the matter of curing the harshness of the reeds, I am afraid there is no other method available in the present case than the very effectual mode of treatment suggested by the "Harmonious Blacksmith" in the case of baby-viz., get it under the blanket-smother it in short. Thus, if there is room between the ends of the pallets and the inside of the key frame, put a strip of wood along the whole length of the instrument, glued to the top of the pan, and a trifle lower than the key frame, it will be about 2ft. 9in. x in. x in.; get a piece of stout brown leather (colour no object), 2ft. 9in. x 4in. or thereabouts, a piece of swansdown, same size, lightly glue the cloth to the rough side of the leather, and when done, glue both on top of aforesaid strip of wood, thus enclosing the pallets (and the sound) in a jacket; this of course softens the flute as well as the clarionette; but as a rule, both are the better of it. Again, if you have no fear of work, and any way handy, a first class method of softening the sound is to lift the key frame up an inch clear of the pan, screw on pieces of wood along the bottom of the key frame lin. thick, and allow them to project inward about in., make a frame, or rather a cover

WATER ANALYSIS, &c. SIR,-In your issue of April 15th, I have read with interest a letter by Mr. G, E. Davis on " Quantitative Analysis," especially that part referring to "estimation of organic nitrogen and carbon." The process there given is that known as "Frankland and Armstrong's." There is also another method known as Wanklyn, Chapman and Smith's, in which the determinations are made in a totally different manner, excepting perhaps ammonia by Nessler test.

In estimating quantitatively the organic matters in water by this mode, Wanklyn first determines the ammonia and urea, and secondly the ammonia derived from decomposition of albuminous substances, and from the relative quantities of each he pronounces the goodness or badness of potable water. This decomposition is effected through the agency of an alkaline solution of potassum permanganate. Of course each inventor claims the superiority of his own discovery over those of others, and I believe that Chapman goes so far as to say of Frankland's process-I write from memory-that the maximum error is greater than the actual amount of organic nitrogen present!

On the other hand, Frankland assumes to show that the permanganate process of Wanklyn is not reliable. However, I understand that this latter discovery in analysis has been adopted by some chemists, notably by Dr. Angus Smith, in determining the organic nitrogen in air. What I am desirous of obtaining is the candid and unbiassed opinion of your correspondent Mr. G. E. Davis-as well as of othersof the relative capability of these two processes which will give the most accurate results, upon which is the most reliance to be placed, in both cases paying due regard to the time consumed, and ensihess of manipulation, together with any other essentail conditions?

REPLIES TO QUERIES.

(2288.]-ADDRESSES WANTED. I have received four or five addresses for "foreign correspondent." Direct letters, including post-stamp for reply, to J. D., Post-office, Melle, near Ghent, Belgium.

[2456]-OLD COINS.-If the querist had read the note, reply to Query 1243, he would have seen easily that it is a Nuremberg counter; that note giving all the principal characters (H.KRAVWINKEL, NUR. R.PF, &c.).: yet several persons made similar queries. Had they observed those characters they would have spared the Editor the trouble of engraving their quite worthless coins.-K. L. M.

It occurred to me that we migh establish one in
Plymouth; but I found on inquiry that the sub-
scribers here belonged to members of all classes of
society, and that, apart of being subscribers to our
journal, there was not much community of feeling
between them. One gentleman I found took it in for
its astronomical information, another subscriber for
its microscopical information, though he complained
that miscroscopical matters had such sparse considera--J. D.
tion in its pages; another for its chemical informa-
tion, and so on. What rather surprised me was the
large number of what I may call well-to-do people,
who subscribed, in comparison to those who may be
termed workmen. As far as I could ascertain, the
ENGLISH MECHANIC is not so much read by intelligent
mechanics as by amateurs, and scientifically in-
clined middle-class people. I am in one respect sorry
it is called the ENGLISH MECHANIC, I wish it had a
more general name such as the Scientific Journal, or
something of that kind. However. I suppose it is
too late now to alter the title. As our readers and
subscribers are in so many respects so dissimilar in
taste and occupation, I think it would be very diffi-
cult to form out of them a new society, and such I
fear will be the case in Edinburgh, Manchester,
Blackburn and other places. I don't say this to dis-
courage our friends elsewhere, but to induce them
to look at all the facts; for I should not like to hear
of them making unavailing efforts to form new
societies, much as they may like to promote a
friendly feeling and mutually instruct each other in
the attainment of useful knowledge. Whatever may
be the result of the experiments made, we are all in
one sense members, as, Sir, you have said, of a national
mutual improvement society. It matters not what we
are, or where we live; we may be millers, or cotton-
spinners, or electricians, or workmen, or students, we
can all be teachers and learners; we can all ask and
answer questions; we can all deposit our mites in
treasury; or, as you have put it, bring our bricks to
the Temple of Knowledge. W. H. J., Plymouth,

EXTRACTS FROM CORRESPONDENCE.

3. The bath may be

[2496.]-PHOTOGRAPHY.-I am sorry that I did not answer this query before, but engagements prevented. A clear glass may be attributed to many causes. 1. The collodion may be insensitive; in that case the same exposure as for sensitive collodion would not do. 2. There may be too much acid in the developer to allow it to work. very much too weak to allow of a deposit. 4. There may be under-exposure. Now I suspect that the last mentioned is the real cause. Of course I am taking a view of the case literally-i. e., a clear (transparent) plate. In the case of a plate having no image, the causes are exactly opposite to those I have mentioned, but then the plate must be fogged, and would be only semi-transparent. If thorough attention to the formulæ advised by me some time ago in the ENGLISH MECHANIC fails of success, why I do not think that I can suggest where the weak point is. If the querist will write a fuller description of his plate I will try and help him further.-MUS.

[2508.]-FASTENING STENCIL COLOURS ON

PAPER-To fasten stencil on paper, mix the colours with dissolved gum.-J. F.

[2528.]-MUSICAL BOX-Harry Bertram, p. 164, in his reply, repeats his lesson very well as far as he has learnt it, but makes a mess of the "Geneva stop" and its action as regards, at least, its effect on altering the tunes, with which the stop has nothing to do at all.

-J. K. P.

[2535.]-OLD COIN.- Perhaps "Bernardin" will excuse my saying that this coin was struck in and not for Dalikarlen, but for circulation in the whole of the kingdom of Sweden.-D. T. BATTY.

[2537.]-WRITING TELEGRAPH.-The mannal "Handbuch der Elektrischen und Telegraphen," by T. Forsach, Vienna, 1854, dscribes the plan of an "American" writing telegraph, of which the two principal parts are two cylinders having an helicoidal isochronical motion, but the name of Meyer is not mentioned in the extract I have seen.-BERNARDIN.

Frankland writes that there is no known means of MR. BEARDSLEY'S LETTERS.-Mr. Dyer says: determining accurately the actual amount of organic-"In printing my note respecting Mr. Beardsley's matter in water, but some general idea may be letters, you have omitted the name of Mr. Carpenter, gathered from the quantities of organic carbon and thereby making me say that "Mr. Beardsley is an organic nitrogen present. It will be observed in his ardent advocate of the views of Parallax,' and has reports of water analysis that the organic carbon and written a book entitled Theoretical Astronomy Exaorganic nitrogen do not bear any relative proportion mined and Exposed," &c. What I said was: "It to each other in different waters; by way of ex- does not appear to be generally known who Mr. Carample, the ratio of carbon to nitrogen in A water will penter is, the referee of Mr. Hampden. He is an be 2 to 1, in B water 5 to 1, in C water 10 to 1, and so ardent advocate of the views of Parallax,'," &c. on. No doubt this difference in ratio is due to the character of the organic matter, whether of vegetable or animal origin. Now what I am desirous of knowing is, are there any means, and what are they, of approximately comparing the organic carbon and nitrogen Mr. C. Nutting, of Digbeth, Birmingham, and Mr. having a fire, the air will enter by any or every means

of Frankland with the old mode of "organic matter" as expressed in grains per gallon? I am aware it would be necessary in the first place to consider whether the organic matter was a vegetable, animal, or, very possibly, mixed character, and a good idea would be gleaned from the proportion of each constituent present, sufficiently so to approximate to the quantity of organic matter.

This would avoid all necessity of evaporating a known bulk of the water and incinerating the residue, when it is desirable to compare with an analysis under the old process.

There are a few queries I have to put, and to which I shall be pleased in having the opinions of your correspondents.

1st. Are both Frankland's and Wanklyn's courses of analysis suitable for waters containing large quantities of organic matter-for example, sewage-and would the processes differ from those applied to ordinary water?

2nd. Can the Nessler test be applied to the determination of ammonia in ammoniacal salts-with previous distillation if required-and as accurately as by triturating with standard acid?

3rd. Is it practicable to determine the quantity of nitrogen present in manures by Frankland's, and particularly by Wanklyn's process, for water analayis,estimating, in the latter case, the resulting ammonia by Nessler, or trituation?

4th. What is intended to be understood by one degree of organic matt er," as stated by Mr. G. E. Davis, page 605, Vol. X.

W. R.

THE ENGLISH MECHANIC. ENGLISH
MECHANIC MUTUAL IMPROVEMENT SO-
CIETY, &c.

SIR-No doubt you have recently had numerous testimonies and congratulations relating to the improvement effected in what may be called, par excellence, "our" Journal. From what I hear in Plymouth and neighbourhood, the number of your subscribers and readers has been very much increased. When it became known that Mr. Passmore Edwards had become the proprietor, if not the Editor, of the ENGLISH MECHANIC AND MIRROR OF SCIENCE, many (and I amongst the number) became subscribers. We had not forgotten how manfully he contested Truro at the last general election. It was, taken altogether, a notable struggle, for though he fought almost singlehanded against old prejudices wealth and territorial influence, most people felt certain he would have been returned, so strong was the current of popular feeling in his favour. But, like many other able men, he was defeated. Possibly his defeat was not altogether a matter of regret, as what the House of Commons may have loss, the ENGLISH MECHANIC may have gained.

If such improvement can be made in one journal in a few months, what may we not expect by-and-bye, and particularly as new mutual instruction societies are likely to spring up through its instrumentality! It is about these societies that I should like to say a word.

BLUE MAHOE WOOD-For the information of
"The Harmonious Blacksmith," Messrs. Mundy, Har-
ley & Co., of 100, Bunhill-row, state that they imported
a little parcel of the wood about two months ago.

Ogden, of Winchcombe-street, Cheltenham, supply
Messrs. M., H. &
fishing-rods made of blue mahoe.
Co. believe that greenheart stands well for fishing-rods
next to blue mahoe wood.

PLAN FOR CUTTER-BAR.-William H. Stone
writes:-"As you were good enough, some time ago,

TOOL

TOOL SET AT AN ACUTE
ANCLE FOR IRON

to engrave a plan for a simple cutter-bar which I sent
you, perhaps the enclosed modification of it for the
tool-post of a screw-cutting lathe may not be without
value. I use it specially for holding the new tools of
Mushet's special tool-steel,' which, if set at the proper
angle, are remarkable for the amount of work they
will do."

66

[2540.]-SMOKE ON WALLS.-Where walls or ceilings are cracked, air will pass in or out, according to circumstances. In the case of an ordinary room, to replace the ascending column in the chimney; where rooms are shut in closely these cracks form the readiest means of admission. Besides the column of air in the chimney passing outwards, there is an upward current in the room immediately in front of the fire, caused by its rarefaction by the fire. This current, on reaching the ceiling, takes a spreading

FRONT

SLOT FOR TOOL

course towards the extremities of the room, the small currents or tributaries take the same course, and prevent any deposit within the area of their immediate influence, while they somewhat retard the force of the main current immediately behind them, and so allow of a greater deposit; so it will be seen that the edge nearest the fire shows a sharp dark line, the opposite being white, gradually softening into the general tone of the ceiling. HARVEY SAUNDERS.

[2548.] GILDING BATTERY. "One in a Fog "has seemingly made a great mistake, He thinks that it is all done in a hurry; let him use only one Daniell's cell, and use sulphuric acid diluted with at least 3 or 4 times its bulk of water. Fill the copper cell with a saturated solution of sulphate of copper, and only put some spare crystals to keep it concentrated on the outside rim. His great mistake seems to be that he expects gold to be laid before there is any in the solution of cyanide of potassium. On the so as to expose as much surface as the piece to be plated), and then on the negative pole put firstly a piece of platina foil until the solution is charged, which can be told by gold appearing on the platinum. Then, and not till then, remove the platinum, and immerse the medal, coin, or whatever it is. If I have taining a few hints which may be useful to him if he time I will send a letter to the Editor next week, conmeans doing the thing practically. Do not have the bath heated above 15 or 20° Reaumur, nor have too great battery power, if you do not wish to waste gold, as it will lay itself in a brown powder if the current be too strong; in fact, with weak currents about 1-50th of the gold is set in powder if you wish to set it any thickness. Carefully weigh your piece, and then you can easily know how much you have laid. As soon as the surface begins to grow dull it would be advisable to take it out and clean it with a stiff brush. from time to time fresh pieces of cyanide of potassium will not be required so frequently if you keep putting forget to have your article to be gilded quite clean, in the bath. Above all things do not be in a hurry and liable to get on the hands in putting the battery and of all things free from mereury, which is very together, for the smallest particle will spoil the gilding.-TANGENT.

THE PHANTOM "WHEEL.-G. Sykes, of Hud-positive pole put a piece of gold (beaten or rolled out dersfield, says :-"Seeing some correspondence in the ENGLISH MECHANIC respecting the Phantom' wheel, I beg to state that I am at present using a pair with india-rubber tires, and I never saw anything to surpass them. They are light, strong, and very easy to drive. The rubber tires do away with all the rattle they do not slip like the iron tires. They are equally and noise, and are a very great help in uphill work, as as strong, if not stronger, than the wood wheels, and not much more than half the weight. I do not find the springiness about the front wheel that Mr. Tydeman objects to so strongly, and think it would have been better if he had tried the wheels before condemning them. I have given them a good trial, and find them." them to be all that the Phantom' Company say of

UTILISATION OF WASTE MATERIAL-A new

utilisation of waste material is reported, from the
Brindisi district, in the oil trade. Formerly the olive
husks, as left by the common oil presses of the coun-
try, were used by the peasantry only for fuel, but a
French speculator is now buying them, at the price of
20f. per ton, and shipping them to Marseilles; where,
after undergoing some chemical process, they are put
into a steam press and made to yield 20 per cent of
oil. The Brindisi people are themselves erecting a
press, capable of operating upon 70 tons of husks per

em.

This

[2547.]-PRINTING NAMES ON PLANS.-Fig. 1 is a tracing of a set square that I made some time since for ruling the slanting strokes of Roman capitals