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APRIL 22, 1870.]

ENGLISH MECHANIC AND MIRROR OF SCIENCE.

grew in profusion on the sand banks. It struck me at the
time that these rushes might be collected and made into
paper. If so, it would be a benefit to many. It would
benefit Cornishmen, who are in rather low water just now
on account of many mining operations being abandoned,
and it would benefit the community by introducing into
the market a new material, whien costs nothing in its cul-
tivation, for making paper. I write this somewhat in
ignorance of the quality of the fibre required in the
material for paper. But I know that the Cornish rushes
are tough, and I should think would be just the thing.
A WEST BRITON.
KELSEY'S PATENT WEDGE-DRIVING DRUMS OR
PULLEYS.

SIR-Enclosed I beg respectfully to hand you tracing
and short description of my patent wedge driving pulley.
On reference to the illustrations it will be seen that
these pulleys are intended for transmitting power by
means of wire ropes, the rope being held firmly between
the sides of the pulley, and thus preventing a "slip," a
difficulty hitherto felt by colliery engineers and others
whose operations rendered the use of wire rope necessary.
These pulleys are extremely simple in construction, and
consist of two loose discs, an internal wedge-ring, and a
boss, or nave, divided in the centre transversely, all the
castings being of an ordinary and inexpensive character.
Fig. 1 is a section, and Fig. 2 a side elevation. The two
discs are made with an angular recess on the inner face
of each, and the centre holes are cast slightly curved
transversely, and made to fit with ease the octagonal
boss. The internal wedge-ring is made with a straight

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point, the periphery being concaved to receive the rope, and, in order to allow for wear upon the latter, the point is also made of less thickness than the diameter of the rope. The nave or boss is provided with a flange cast on each end, which flange is for the purpose of retaining the disc in position. The nave is faced and bolted together and bored out to fit the driving-shaft, to which it is secured by means of two short keys, driven from each end. The action of the pulley is brought into operation by means of the pressure of the rope being thrown, on one side of the pulley, upon the internal wedge-ring, which is thereby forced against the inclined faces of the recess in the discs on the other side of the pulley, the result being that the discs are driven apart on the bottom side and towards each other, so as to compress the rope on the top side.

The practical result of the trial of these pulleys has proved the principle to be a correct one, and, as there are not any parts to get out of order, their use must be attended with considerable economy.

WM. KELSEY, 18, Cannon-street, E.C.

DODS' ELECTRICAL PSYCHOLOGY. SIR-Lest the commendation bestowed on this work by Mr. Dineen. p. 91, should induce some of your readers their who are interested in these subjects to throw away money by buying the book, I think it right to say that it is one of the most pretentious pieces of rubbish ever published. Its author is one of those claptrap talkers who pour out streams of high-sounding verbiage without the trace of an idea; in fact, he is a mesmeric Barnum.

The quotation given, "it will be readily perceived by any one acquainted with electric science," &c., is enough proof, for the following statements no such person would endorse; but the Doctor's idea of electricity is the wildest nonsense. He talks about the gold and the chloride of lime in electricity, &c., and describes electricity as the source of matter, and containing in itself all matter, and talks generally with the usual sublime impudence of the charlatans who invent systems and impose them upon others who know just as little as themselves of what they are professing to explain.

As to positive and negative. they are terms only; their value depends on the sense we put on them. That the human body displays polar actions, like magnets, there is little doubt, and the study of this by Reichenbach is a valuable contribution to knowledge, very different from Dode' assumptions, which are so gross as to destroy the value of what he says as to the facts and actions which he describes in common with all other writers on the subject. Finally, J. B. Dods was not "the discoverer of electro-biology," but simply a peripatetic lecturer thereon.

SIGMA.

A POOR GLASSBLOWER'S QUERY. SIR,-The readers of the ENGLISH MECHANIC are greatly indebted Mr. Joseph Leicester for his clear description of glass-making and staining. I should like to see him give the poor glassblowers who cannot afford to make new glass a hint or two how to colour old metal, say a pot that will hold from half a hundredweight and upwards, a cheap dark ruby from zatinium ore and copper, Also the proportions for a half hundredweight of metal. what amount of oxide of chromium would do for a half hundredweight to produce a good colour? Then, is there not a rich colour derived from uranium, lemon yellow? Also a cheap opal from bone ash and carbonate of barytas?

HANLEY.

P.S.-I might be able to give him a few colours for glass

in return.

SEWING MACHINES.-II.
(Continued from page 90.)
NEEDLES.

K

drawn off at the back, as represented at E. Into this loop the point of a shuttle, or the hook of a lockstitch machine, enters, so that the whole length of the under thread is carried through the loop; both sides being tightened at the same instant.

THE LOCK-STITCH.

SIR,-The needle is the accompaniment, if not the
pioneer, of civilisation. It is a rare or a make shift thing
in savage life, and its withdrawal from use would be a
This application of needle and shuttle to a sewing
sore trial to such tempers as cannot bear the acciden-
machine was the invention of the late Elias Howe,
tal absence of a shirt button. We can purchase a
Maturing his
packet of needles for one penny, and seldom think it a Jun., of America, whose career as a mechanic is one
of the most extraordinary on record.
marvellous production, or estimate the accumulated
skill that has brought this, the lightest and most ex-invention kept him poor, and then he had to defend
his rights at law, finally obtaining royalties from the
The majority of the mothers and daughters of Eng- American sewing machine makers which amounted to
tensively used tool, to its present perfection.
land ply their needles at the rate of 30 stitches per a very large yearly income, in addition to the large
minute; many, more fortunate, make from 500 to 2000 profits he made in the manufacture of the Howe sew-
stitches per minute by using the sewing machine, while ing machine.
others have given up machine sewing in disgust, hav-
ing selected a bad machine, or, having been misled by
some vendors who professed the thing could be learnt
in an hour or two, and without trouble.

Let the disappointed try again, and be content to proceed slowly, but surely, acquiring first a rudimentary knowledge of the action of the needle, and the shuttle, spool, or looper employed in the formation of Figs. 1, 2, 3, and 4, represent a sewing machine needle

the stitch.

FIC.S

enlarged. A, the eye of the needle; B, the front or
long groove; C, the back or short groove; D, the fabric
under the needle: E, the thread, showing the loop
formed under the fabric, and the cloth plate or
table F.

Most persons on first seeing a sewing machine needle
feel surprised at the eye A being near the point, and
are perplexed to understand how the thread forms its
in the needle the thread would be liable to be broken
loop a thousand times per minute. Without grooves
on entering the fabric, but laying in the grooves B and
C, protects it from cutting and fraying. If it were
necessary to prevent the formation of a loop the thread
would require to be drawn out faster than the needle,
it being double the length of the needle through the
fabric; it is this extra length which forms the loop in
connection with the pressing of the fabric against the
thread and needle, preventing the thread rising with
the needle. The front groove B is large enough to
allow the thread to pass up with the needle, while it is

Fig. 5 represents the formation of the Howe or shuttle stitch, the upper, or needle thread a, laying on top of the fabric, and the lower or shuttle thread b. laying below the fabric, the threads being interlocked at ecce with each other in the middle of the fabric between the four stitches.

It is the strongest stitch made, and cannot be rathe least quantity of thread, it is in general use, withvelled. The stitch being alike on both sides, and using out complaint, unless badly made by an inferior machine, or an incompetent operator.

Fig. 6 shows a front side, and Fig. 7 an end view of a shuttle and needle, the arrows showing the direction of their movements when about to pull up a stitch, and they are so timed or adjusted as to complete each one its stroke at the same instant, so that the shuttle pulls forward, and the needle upward, giving a pull of the two threads in like manner to the shoemaker when stiiching the sole of a boot.

R is the shuttle reel. After winding the thread very evenly upon it by the machine, it is placed in the shuttle, and kept in a position by a spring or catch so as to turn freely. The thread in working off it is directed from the underneath side to a hole in the bottom edge of the shuttle passing outwards, then by a hole adjoining it returns inward, then to holes in the front end, and to the outlet holes in the top edge of the shuttle to the fabric. A spring in the front end of or strain on the thread, gives the operator the power the shuttle at T, with its screw to regulate the tension in conjunction with a tension on the needle thread, to interlock the threads in the middle of the fabric; or if preferred, to pull one thread tighter than the other according to the requirements of the work in hand.

H is a part of the needle bar, into which the needl is inserted and fixed by a screw I. In the return strok the needle descends through the fabric, the need! hole in the cloth plate, and into a slot in the metal K against which travels the face of the shuttle. If the parts are not truly fitted and well polished, th

machine will be very troublesome, although the work-fitting is the reason for my liking my specimen so manship of other parts may be very good. A PRACTICAL MAN.

LATHES.

SIR,-In my letter on the subject of the SaltaireWardour-st. lathe, you have altered my sense in the 24th line by inserting the word "cut." The cutting would be the least part of the expense of steel wheels, as, when once forged and turned, the cutting would be done with no more difficulty in steel than in brass, only taking a longer time to accomplish. In the slide rest of that lathe there are several small wheels cut out of the solid steel, besides, if I recollect right, a rack for one motion, and a segment equivalent to a portion of a large wheel for another During the past week I have had to cut teeth of in. pitch, in. deep, and through cast steel fin. thick, which took 3 minutes each to do, so the cutting, alone, of a set of wheels would not come to very much money, but I am not prepared to say where the necessary forgings could be got done, up to 9 or 10 inches in diameter, and soft enough to be cut at all. J. K. P.

RHEA GRASS. SIR,-The following information, which I copy from a contemporary, may be acceptable, supplementing as it does that given by "Minnehaha" in your last number. D. V.

"The great drawback which has hitherto prevented the utilisation of this grass has undoubtedly been the difficulty of extracting the fibre, the manual process being so expensive as almost to amount to a prohibition of fibre manufacture being carried on. During the last twenty years or so, a number of machines have been brought out for extracting fibre, but none of these have been considered entirely satisfactory. Up to the present time, the common mode of extracting the fibre from such plants as the aloe is by soaking the leaves in water till the vascular matter has become rotten, and then beating off this decayed matter from the fibre with a wooden mallet, or scraping it off with a blunt knife. This process is not only a slow and nasty one, but is attended with much waste of fibre; it also discolours, and, what is most important of all, weakens the fibre. At the London Exhibition of 1862, two American gentlemen, named Sandford and Mallory, exhibited a machine for extracting fibre from aloe, plantain, or pineapple leaves. This machine has been used in America, but would scarcely be found either sufficiently simple or cheap for the ryots of India, its cost being about £45. What is wanted is a cheap machine of simple construction, by which the fibre can be easily extracted; and we think it only due to those of our readers whohave contemplated entering the competitive list for the above-mentioned prize to state that a machine, possessing, so far as our present iniormation goes, all the necessary requirements, has already been invented in India by Mr. Donald Cruikshank, representative of the Telegraph Construction and Maintenance Company. No preparation of the leaves is required for this machine; they are taken to it green, just as they are cut from the bushes, and in the wonderfully short space of two minutes, the fibre in the leaves is brought out stripped of vascular matter, and in admirable condition. The rotting process not being necessary with this machine, the deteriorations in colour, as well as in the strength and fineness of the fibre which follow upon the adoption of that process are avoided. A correspondent of an Indian contemporary asserts that the samples from Mr. Cruikshank's machine were "fine, delicate, and even; not one was cut or broken; and the material would readily fetch £50 a ton in the home market." Assuming that the efficiency and simplicity of the machine are equal to anything that is likely to be set up in competition with it for the offered prize, we very much doubt whether it is likely to be surpassed in point of cheapness. It is so easily taught to use it in an hour's time, and its construction worked, we are informed, that any native may be is so simple that it can be sold for 10 rupees (£1 sterling). We hope shortly to be able to give some further description of this machine, which, if equal to the opinion as yet formed of it, from its experimental results, seems calculated to meet a want which is not confined only to the fibre-yielding plants of Eastern

India.

CASE HARDENING.

SIR,-If I may, I beg to inform "St. George" (p. 54), that I believe Mr. Armitage's method of case hardening or complets hardening is not only new but that it is the best for engine and machine gearing. During 24 years' experience at some of the leading engineers, such a process has not been adopted. For two steamboat companies and an eminent firm of engine makers, I have case hardened the gearing of several pairs of vibrating steam engines, but not by the plan of immersion. If the granting of a patent to the gentleman would do him some good I verily believe that it would not do any manufacturer the least harm. By the process in question, would" St. George "inform me what quantity of the prussiate of potash would be required to thoroughly harden a crank pin or a piece of iron of the following dimensions:-15in. long by 4 in diameter, and how many times the retort would have to be fed with prussiate of potash before the article would be ready for cooling?

R. E. T.

BENNETT'S CHUCK. SIR,-In reply to "I. N. G.," anyone accustomed to turning knows that a hammer is constantly used for setting work true in all sorts of chucks; this is no exception, but it is, perhaps, rather a weak point in this one that after you have got your work to run as true as may be with the help of the hammer, the big screw still wants tightening, which must, to some trifling extent, alter the setting of the work. In my description of the chuck on p. 41, 23rd line, the word that being omitted before "the reason," makes me too willing to admit that defective

little as I do; whereas I do not, on the whole, think it anything like so good as the one I call mine, figured October 22nd last year (or Feburary 18th this year, with the addition of a shield for the hands), which I have been using constantly for 12 years, and cannot suggest any improvement in. The 4-dog-chuck is the king of chucks for everything above lin. diameter, and mine the best for everything under that size. Universal chucks, with right and left-handed screw, and 2 dogs only, are very well for amateurs, possibly, but are a delusion and a snare, and, I should think, not an effective snare for a practical man. Clements made three of them, I believe, for his own use, and any one of the three fitting interchangeably on four different lathes in his shop. I am, as I say above, not a believer in them, any more than I am in Clements's driver chuck, which you find put on all high-class lathes, bound, as I must be, to admit that Clements was a man of extraordinary talent and, perhaps, the best mechanician of his day. J. K. P.

FRAUNHOFER'S LINES.

SIR, I have a grave suggestion for Mr. Proctor's consideration, regarding the origin of the dark lines crossing the solar spectrum. They are generally supposed to be caused by the absorption of those rays from the body of the sun by its luminous atmosphere, which that atmosphere itself emits.

I do not like to be continually at variance in my opinions with the rest of the scientific world, but greatly doubt whether these lines have not their origin nearer home, and represent the absorption of those portions of the solar beams by the chemical action established in their passage through our own atmosphere.

ASTRONOMICAL.

T. A.

SIR,-1. I should be glad of an explanation of the reason why, in Dietrichsen's Almanac, the time given between the rising and southing of a star is four minutes less than between its southing and setting. I do not see what connection there is with the fact that a star sets four minutes later every day. 2. Will F.R.A.S." kindly tell us how he succeeded, with the object glass he commenced some time ago? 3. Sir John Herschel states that "the total thickness to be abraded from the edge of a spherical speculum 48in. in diameter, and 40ft. focus, to convert it into a paraboloid, is only 1-21333rd part of an inch.' How is this result obtained?

SIR

FRANK FOTHERGILL.

THE SUNFLOWER. -When I think of the many uses of this plant, and of the great ease with which it is grown, I feel surprised that it is not more largely cultivated. It ought to be, if properly grown, far more productive than barley, as food for poultry, who are very fond of sunflower seeds, and eat them greedily. This climate is not exactly suitable for the growth of buckwheat, the seeds of which are excellent as food for fowls, but if it were suitable, there can be no doubt that it would be extensively grown, and since that is impossible, we may regard the sunflower as a good substitute. It will do for poultry of every description, and it grows rapidly and readily, almost anywhere; it gives no trouble. I have grown it to a gigantic size, 9ft. or loft. high, at all events, with exceedingly large heads,

full of hundreds and hundreds of seeds, and this too without any trouble whatever, and without any manuring or preparation of the soil.

There are tall and dwarf varieties of the plant, but the above-mentioned size, equalling in fact the Helianthus Californicus, I can only attribute to some peculiarity in the soil or in the air. If there be sunand it takes up a great deal of moisture, and if planted shine, it will certainly grow vigorously in damp lands, would contribute to the health of a place by assisting in the destruction of the various miasmata which have such deadly and potent effect on human beings. A saline atmosphere is no obstacle to its growth; on the coutrary, it grows well when sown near the sea. There is a considerable quantity of pith in the stalks, which I should think might be used to some profitable account, and the stalks themselves, if broken up and well dried, form an excellent sort of firewood. The seed is not perishable, and with proper precautions may be kept a very long time in good condition. The stalks, when burned, yield potash. In many instances, several heads will appear on one plant, but it is advisable to destroy all of them while young, except the largest, which will then increase in growth, and

on an extensive scale there can be no doubt that it

furnish an abundance of rich seed.

THE ARITHMOMETER.

TAUTAU.

SIR. Our old friend, the arithmometer, or calcu lating machine (by which all the rules of arithmetic are worked, and calculations of the greatest intricacy, both for financial and scientific pui poses, performed with unerring accuracy and promptitude), is gaining favour in England, as evidenced by its employment amongst the most eminent engineers and leading actuaries, and also in Government offices; yet its progress here is slow, considering its merits, compared with what it is in France, which, it should be borne in mind, is the country of its origin. This restriction to its usefulness is doubtless in some measure also due to the inventor not being, like many inventors, a needy man, and leaving the instrument to work its own way.

In bringing out the arithmometer, M. Thomas de Colmar proposed combining cheapness with simplicity of construction and portability, a problem which, at that time (nearly thirty years since), appeared of doubtful realisation. M. Thomas de Colmar, however, applied himself to the task with the energy of a man determined to conquer all difficulties, not the least being his ignorance of practical mechanics, and by dint of time, labour, and expense, he succeeded in

producing an instrument which, in principle only, was similar to the present. The perfecting of the arithmometer, from its primitive form, was still to be accomplished, and it was not till after many years of practical experience that it was brought to a state of efficiency. Indeed, it is only recently that the latest improvements, or what we may call the finishing touches, have been applied, by which its manipulation is rendered as easy as child's play.

Although the inventor's first object was to supply the want of his own peculiar sphere (insurance companies), it may be readily conceded that his idea soon took a far wider flight, and suggested its employment in the various branches of commercial enterprise, in most of which the arithmometer is now employed in France, as also by bankers, philosophers, and men of science, by whom it is found to effect a great saving of time. It is coming into use in Russia and America, but there high protective, almost prohibitive, duties are a bar to its rapid development.

The instrument is a marvel of rapidity, and those who feel interested can see its manipulation at my office. Since writing the above, I have heard that M. Thomas de Colmar died on the 1st of March last, in the 85th year of his age, acting until then as director of the Sun Fire Office. L. DE FONTAINE MOREAU, 4, South-st., Finsbury.

INDEX FOR DIVIDING PLATE. SIR,-Allow me to suggest a trifling alteration in the usual arrangement of lathes for ornamental turning, which, however, I do not in any way claim as an idea of my own or a novelty. It is that the index, or spring point for the dividing plate, instead of being placed, as it generally is, on the near side of the mandrel (that close to the operator), should be fixed on the side farthest from him; mine has been in the position I propose, for many years, and though at first it seemed a little awkward having to stretch the hands across the mandrel for every change of division, I got used to it almost immediately, and soon found the convenience of the new arrangement. The advantages are, instead of the head of the index coming between the eye of the operator and the hole into which the point is to drop, as it does in the ordinary plan, you look, as it were, under the spring, and have the division always in sight; the light falls much better on the divisions, and, if necessary, it is easy to throw additional light on them by placing a piece of white paper in such a position as to reflect light on the dividing plate, which cannot well be done on the near side.

Though I almost invariably use
the index as I have described it,
I still retain one in the ordi-
nary position, so that, in case of
requiring unusual steadiness in
the work for some special pur-
pose, I can use both the indices at
once, in opposite sides of the
mandrel.
The upper end of

each index is carried round into
a curve, and bent back so as
to form a convenient handle to
take hold of, as in the accompanying figure.

STAINED GLASS.

G. C. C.

SIR,-In answer to Gustavus Knox's question 2233, No. 261, I have been doing all I can to give him the information he desires. The following is the result of my inquiries:-There is only one stala used for glass in England, that is yellow. There are many different shades, but they have all one base-namely, silver. The flux for silver is antimony; the silver is melted in a crucible, when melted, it looks like a black deposit, and is put into clean water from the crucible, red, or common red ochre, which forms a vehicle for then it is ground as finens the finest flour; when required for staining, small portions are mixed with Venetian the silver. The ochre and silver are ground to the consistency of very fine flour, and by adding a little gum water, are made to follow the brush just like paint. It is laid or flowed on the glass according to the desigu required, rather thick; it is theu allowed to dry, then placed in the burning oven; when it has been subthe grating of the oven is pulled out, and when cold, jected to a gradual moderate heat for about four hours, the silver has eaten in the glass, produced a bright yellow stain, while the ochre washes off with the

greatest ease.

If a deep yellow is wanted, the proportion of silver is increased, and just as the yellow is to be light or dark, so is the amount of silver regulated. "The reddish brown" stain is produced by using brown enamel; the blue, by using blue enamel, and the different shades of all colours, except yellow, are produced by using enamel. The enamel is ground very fine, just like paint; a large slab of glass or iron is used. The ground enamel is placed upon it, and a large glass crusher is rubbed upon it by hand until it can be worked just as paint is worked. The lux (glass and red dead) is also done the same as the consistency of paint, and, when painted on the glass, as enamel; both are worked to form a substance of the required, the flux leaves the enamel to melt in the window-glass, and produces the beautiful colours referred to. There is great art in the burning of the practice. The glass itself is so various in its nature colours in the glass; success is only attained by long with regard to being hard or soft that only those who by long practice in the business have come to understand these things are fit to become glass stainers. Jos. LEICESTER.

ROTARY ENGINE. SIR,-I have noticed several specimens of rotary engines in the ENGLISH MECHANIC, and if you think this worthy of your notice, I shall feel obliged to you for its insertion, as it may be of use to some of the readers of the ENGLISH MECHANIC. It is called Hammond's rotary engine. A, Fig. 1, is the outer box, which is stationary, with the end or side plate

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off, showing the interior; B the inner box, which revolves; D pipe for conveying the steam to the cylinder; G waste steam pipe; F a sliding plate through the outer box; E a spring to keep the plate close to the inner box. While revolving, the steam enters at P and make its exit at R, whereby a rotary motion is obtained without compressing the steam again in the engine before it can make its escape, which is the case in most rotary engines. PHILIP.

SLEEP.

SIR,-In your issue of April 8, I find a scrap of information at the head of the section of your paper designated "Chips," which I should like further information upon. The passage reads as follows :-" M. Sommer propounds a new theory of sleep; his idea is that sleep is simply a result of the deoxygenation of the system, and he believes that sleepiness comes on as soon as the oxygen stored in the blood is exhausted," In the first place, should like to know who M. Sommer is, and in what particulars his theory differs from the popular theory. The fact is, I very much desire (by your permission and through your invaluable paper) that the subject (sleep) should be thoroughly ventilated-i.e., come to some conclusion, scientifically, as to what sleep is, and what is the cause of sleep. Personally, I should be much obliged if any one of your numerous correspondents could point me to a good work on the subject.

СОМА.

GEOGRAPHY AND EMIGRATION. SIR,-There are two reasons why I should be very careful when writing anything for insertion in the ENGLILH MECHANIC. The first of these is, that your space is very valuable, and, therefore, it is desirable to say what we mean in as few words as possible. Secondly, my time is limited, and upon this score fancy must never be allowed to rohin. You have kindly intimated that space is at my disposal to give epitomised accounts of the transactions of the Royal Geographical Society. It has struck me that whilst doing this I can be of much more service to your readers, and supply a vacuum in our periodical literature. Emigration is, and has been for a long time, a standard topic for conversation and debate throughout the length and breadth of the country. There are questions-and are very difficult ones to answer- which arise upon the first thought of emigration. When shall I go? What country or colony am I most suited for? To answer these questions it is necessary to be acquainted with the various natural characteristics of the colonies, &c., open to emigrants, their climate, fauna, flora, &c. Now, Sir, backed up by the splendid library of the above-mentioned society, I think if your readers who wish for some instruction regarding geographical matters will kindly forward queries to you in the ordinary way, embodying in them their special requirements. I shall be enabled to give the iLformation required at an early moment. F.R.G.S.

BEES.

SIB, As I see a proposal to have space in the ENGLISH MECHANIC for amateur farming, I would, in the event of such space being given, say a word on profitable bee-keeping. I learnt my lesson from ths aged apiarian, Mr. Payne, of Bury St. Edmunds. He always asserted that it should be made a paying business; and if. on an outlay in the spring of 10s., one hive will, as is often the case, produce 161b. of honey, and more, it would go a long way towards paying the rent. Mr. Payne, although having all the new inventions of his day, yet adhered as a rule to the flat-topped straw hive, with a hole 4in. in diameter on the top, which was plugged up in the winter, but which in honeymaking time was taken out and a smaller hive of straw, or a bell glass, or an old tea-chest, placed over it. In a "cap," as it is technically called, of the latter kind, I have myself secured 161b. of honey in a few weeks. The hive itself should not be fastened on its stand by mortar; we may leave the bees to do that; they will do it effectually. A straw roof to preserve

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FIG. 2

from the weather is very picturesque, but is a great
evil, as it harbours earwigs and a host of enemies to
the bees; an old cracked red basin, or, in fact, any-
thing but straw, to keep the wet off is all that is needed.
Besides, these straw roofs are generally fixtures, and
then the impossibility of taking the honey without
killing the bees. All observations, and as much of
necessary work as is possible, should be carried on in
the year.
With quietness and self possession, the bees
will never sting. I will add no more.
ONCE A BEEKEEPER.

THE PHANTOM" WHEEL.

SIR,-Will you kindly allow me to ask those of your
readers who are not yet our customer to suspend
their judgment for a week, alike upon the claims
and the condemnations put forth in the modest letter
of Mr. Edmund M. T. Tydeman, which appeared
in your last issue. Pressure of business of other
kinds, and the very limited time within which I
understand you will go to press with your next
number, prevents me from now dealing with the
subjects.
J. A. MAYS, Secretary and Manager, Phantom Veloce
and Carriage Wheel Company.

DR. KITCHENER'S TELESCOPES.
SIR,-I am glad that an inquiry for Dr. Kitchener's
telescopes has been made. I hope that some of our
many readers who are interested in astronomy will be
able to answer the question.

EXTRACTS FROM CORRESPONDENCE.

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A GOOD SUBSTITUTE FOR BINDING SCREWS. -E. C. Murray writes as follows:-" I send the following, thinking that it may be of service to those of your subscribers who have, or are about to construct bat eries in which "carbons" are used. Bore a hole in the top of the carbon in. deep, and about fin. in diameter, scrape it out towards the bottom so that it is rather larger than the top; procure a piece of stout copper wire about 8in. long, bend the end,

thus,

}

make the end of carbon hot in a clear fire

take itout, place the crooked end of the wire in it and fill it in round the wire with some solder (which should be melted in a small ladle). Of course the other wire may be soldered to the zinc. To connect the batteries. I clean and lap the ends over in, and bind them with some fine copper wire, which must be clean.

THE ENGLISH" VELOCIPEDE.-"Over Sixty" says:-"Living in a country where there are many hills to mount, I am always looking out for a three-wheeler that will really go up hill. I want one for use, and not for mere amusement. It strikes me that the arguments of A Thinker' in favour of the front guiding wheels bearing the load are good, but the principle of his machine seems to me to be précisely similar to the Edinburgh' velocipede, manufactured by Mr. Brown, 67, St. Leonard'sstreet, Edinburgh, the latter having a much lighter appearance on paper than A Thinker's.' The Edinburgh' weighs from 54lb. to 60lb., but in the drawing of the Edinburgh,' although evident that the guiding apparatus is on each side, it is not made plain what the contrivance is. The driving wheel behind is higher than the two front guiding wheels."

REPLIES TO QUERIES.

[1875.]-ANGLE IRON HOOPS.-"N. B." can find the length of angle iron for the hoops, by adding six times the greatest thickness of the iron to the circumference of the hoop, which can be found by using the rule given by "Leo I.," p. 510, Vol. X., and for the length of the iron for the hoops, with the flange on the inside, subtract six times greatest thickness from the circumference of the outside diameter. In the two

hoops that he gives, first one, 2ft. diam. inside, with flange on the outside, circumference 2ft. = 75 3in., add 6in., which is about six times the greatest thickness, and it gives 81-39in. 6ft. 9gin. for the length: the other one, 2ft. diam. outside, with flange on the inside, subtract 6in. from 75 3in. = 69.39in. 5ft. 9 in. This rule was given to me by a foreman boiler maker.SCIRE VOLO.

[2000]-PROBLEM.-In the first number of the present volume, there are solutions to my query, and the result in each case is, that "the difference between P and Q is equal to half the difference between the weights of the arms," which is not the solution asked for in the query. As the answerers of the problem doubted the correct copying of it, I wrote to or three from "Todhunter's Mechanics for Beginners," chap. weeks ago, informing them of its being correctly taken XII., sum 12. As my answer did not appear in your paper, I presume it was overlooked, and I again beg to thank "Franck " and others, who solved the problem, and should be glad to know whether the sum or the answer is worded incorrectly in "Todhunter's" book.

The author of The Cook's Oracle" had, for his time, one of the finest collections of instruments in England. No expense was spared by him in the pur-Y. P. W. chasing, and no one knew better how to preserve the [2143.]-SOFTENING CAST IRON.-" Blue Ruin " objectives from injury. I am therefore inclined to think that wherever they is in error when he states that "G. B. K" cannot now are there must be some of those fine treble object-soften cast iron. He can do so by heating the metal glasses made by Peter Dollond a hundred years ago. to a bright red, cooling quickly in water, reheating, I have heard the work done then was superior to and then annealing by cooling slowly in ashes.-J. B. much for some time afterwards, though, I have no [2153.]-VERTICAL SAW FRAME.-I doubt very doubt, inferior to the productions of our best artists of much that " J. T. W." would ever get a frame to cut the present day his oak logs, unless he went to an enormous expense, that is if the timber is English oak, at such a place as Sunderland, for wood ship building. I never knew the English oak cut up with the frame, unless it was pretty straight along the bottom, or was first sided up on two sides.-MILL SAWYER.

Still, a great interest attaches to these telescopes. It is well known that some fifty years ago Sir John Herschel published his formula in the "Philosophical Transactions." And he says in 1861 that they still are generally the tables used by our best opticians. But when Dollond made these triple object-glasses, no tables practically of any value were in existence. I suppose he found out the curvatures by successive trials.

Mr. Webb need not be afraid that we shall be weary of his "Hints." Anything from the author of that delightful book, "Celestial Objects for Common Telescopes "-a book which has made more astronomers than any other in the English language-will always be received with pleasure.

Will any of your readers kindly state the smallest aperture with which they can see the comes to Rigel? I have found 2in. show it well when the night has been by no means good.

I entirely concur with "F.R.A.S. " in thinking that 4in. is the very smallest object-glass which will pick up six stars in the trapezium.

I am glad the name of Mr. Wray has been lately brought forward. I have seen some fine work done by him, and his prices are extremely moderate-which just now is a great recommendation.

STELLA.

PRESENT STATE OF OUR KNOWLEDGE OF

METEORITES.-Herrr Rammelsberg, of Berlin, has
just given a summary of what is known, from a
mineralogical and chemical point of view, of the
meteorites, those me sengers from other heavenly
bodies which from time to time reach our earth. The
essential constituents which are always present in
very distinct classes of these foreign bodies are
nickel, iron, phosphorus, sulphides of the metals,
oxides, silicates, free silicic acid, and, in rare instances,
carbon, or combinations of carbon. The same subject
is treated at great length by M. Daubree in the
Journal des Savants for Jan., Feb., and March.

[2184.]-SULPHATE OF LEAD BATTERY.Will "A Good Boy" please say whether he amalgamated the zinc plates to his battery, and will some experienced contributor inform me if it is better without?-PLUMB. SULPH.

[2223.]-ENGRAVING ON SLATE.-I see two correspondents giving advice on this, but I doubt the querist will be much aided by it. I have cut some thousands of letters on slate, and my mode is, draw in the letters with a blacklead pencil, if wanted very accurate, come over with a draw point, taking a square graver, cut a deep bold line up the centres of the letters; this line if done with one cut will be broken and jagged at the edges, then take a flat tool (a tool about a quarter of an inch broad, and sharpened exactly the same as a joiner's chisel, but mounted in a graver handle), and with the flat side to the slate, cut from the centre stroke to the outside edge of the letter, holding the tool so as to cut the outside of the letter bevelled; it cuts as clean as a bit of cheese, the letter when finished being deep in the centre and bevelled off to either side.-I. N. G.

[2233]-STAINED GLASS.-See answer by Mr. Leicester among the "Letters to the Editor."-Ed.

E. M.

[2286.]-DIRTY CEILINGS.-Only ceilings, the outer portions of which are exposed to the influence of temperature, have the " ribbed" appearance. In da np weather the plaster absorbs moisture, the dust and smoke adhere to the damp portion; the joists keep the plaster dry, hence that portion is less dirty and smoke-stained.-THE WELSH SHEPHERD. [2263.]-AMBER.-Amber is soluble to a certain extent in alcohol, ether, chloroform and turpentine.BETA.

95 in. to the foot. A board should be cut out and boat
built up to it.-MATY.

[2270.]-MOTION OF WATER.-38 × 25 depth of water in feet. 95 x 81 785 the velocity of discharge in feet per second; diameter of orifice lin. 00546; the area in square feet

78 5 × 00546 × 60 = 257

cubic feet discharged per minnte.-ANTHONY.
[2293.)-NICOTINE. "Maues" should put two
drops of oil of sassafras on his pipe of tobacco, which
will entirely prevent vertigo, and all the other disa-
greeable effects of smoking.-VIATOR.

[229]-THEOREM.-It seems to be a particular case of the theorem "the circle is greater than any isoperimetrical figure," which is proved in several authors.-A. BLANCHET.

[2296.]-DIE.-I think "Cantab" would have a great trouble to cut a good counterpart to his die with tools. A much better plan would be to stamp a copper counterpart with the steel die itself, provided it is hard enough. If it is not, he must harden it by one of the many recipes given in these pages.-W. H. ТПОВРЕ.

[2297]-VIOLET INK-Boil 4oz. of logwood in 14 pint of water to one-half, strain, and aid 6 dr. of gum and 14oz. of alum; set aside for 12 hours, and decant for use.-BETA.

[2309.]-ETCHING ON GLASS.-- To etch on glass with fluor spar, cover the glass with beeswax by melting the wax and running it over the glass, about 1-16th of an inch thick, then write on it with a needle' after which sprinkie some fluor spar upon the writing. and pour sulphuric acid on it, let it stand for 10 or 12 hours, then wash off the superfluous acid, and take off the wax and wash the glass clean, and it will be seen that the fluor spar has eaten away the glass on those parts not protected by the wax.-PRACTICUS.

of this cone must of course be inclined at 70°, then a tangent to the base of the cone passing through the [2324.]-GYMNASTICS.-Let "Gymnastikos" char horizontal trace of the line, will be the horizontal the ends of the posts that are let into the ground, and trace of the second plane (H T2); the plan of the line of they will last a very long time indeed; another plan intersection of these two planes must pass through the is to steep them in creosete oil a week or so before putt-plane of the apex of the cone, and through the intering down.-MILL SAWYER. section of the horizontral traces of the two planes. It is easily seen that the horizontal trace of each plane is

[2341 AND 2355.]—CANOES AND BOATBUILDING. I have seen several inquiries on this subject, and had hoped that some abler pen than mine would have answered them. For the benefit of canoe builders I give below the dimensions of the Rob Roy class, as published by the club:-Length over all, 14ft., beam outside, 26in.; depth from surface of deck at fore end of well to top side of keel 11in.; keel to project lin. outside, and to have lin. camber or round in its length. The best material for wear is English oak cleaned up to 5-16ths of an inch thick, but for lightness, white fir or white or yellow pine are used. In answer to "C. D. R." the keel should be of oak or American elm; the timbers or ribs of the same, or ash; American elm is the best in my opinion. The stem and sternpost are worked of oak grown to about the right curve and scarphed to the keel. In building, the strakes or planks are worked first, and then the timbers are steamed and bent in and fastened while hot. I shall be happy to furnish sketches of any parts required, or to give any information in my power on this subject or yacht building to any who may think of attempting this pretty art.-BOATBUILDER.

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[2346.]-GEOLOGICAL MANUALS.-Having regard to the limited prices, there are only three published in England-Jukes's, Houghton's, Page's, the publishers are knowu to all booksellers. I will now pass my opinion on these; they are all good works, but the ground of preference must depend on the student. If he likes a book that has "grit" in it, technical and directly, ad rem, and is not afraid of a hard book, let him buy Jukes's; I like it myself, because conceited enough to undervalue popular works in the popular style of science. If something easier and more diffuse would suit, why then order Page's Advanced Text Book;" the other, Houghton's, has peculiar features of its own; does not so much allude to English examples; has a good deal to say about distribution of the organic life on the globe, the orders, their first appearance, and their extinction; takes a glance at the "plasma " of the earth's crust, and such perpendicular to the plan of the line of intersecexamples. It would not hurt a student to buy, at tion of the other two planes. Then, if we draw a line intervals, each of the works named. I could give perpendicular to the line of intersection, and passing advice as to an early course for a student, but to do so through the horizontal trace of the perpendicular line, effectually I should require to know something of his we have the horizontal trace of the third plane, and a previous education, his means, his opportunities, his line drawn through AO will be the plan of the second locality, &c. Perhaps I may put together a few hints line of intersection. The third line is drawn from O to B, then having got the horizontal traces and one of on the subject for the ENGLISH MECHANIC, at no distant period; meanwhile, I advise the student to the vertical traces, it is an easy matter to get the other hang on to the skirts of the nearest practical geologist making an elevation on a ground line, perpendicular two. The inclination of the third plane is got by he can meet with. Publishers: Jukes, Black; Page, to its horizontal trace. Draw y' perpendicular to Blackwood; Houghton, Longmans.-F. S., F.G.S. H T3, and project the point O perpendicularly through [2346.]-GEOLOGY.-One of the following works, then set up the height of the point O' taken from might suit:-"Page's Textbook," price 68., Black- the other ground line (r), then a line vt, drawn wood; "Jukes's Geology," price 12s. 6d., Black and through this point, and the intersection of the trace Co.; "Phillips's Treatise," price 78., Longmans. - with they will give the inclination required, which is 468.-M. WHEATLEY.

[2331-PATENT DRYERS.-The mixture is con-
sidered a secret, but the following may be the material
chiefly employed:- Proto sulphate offiron (greeu cop-
peras) is put in a clean iron pan upon a clear low fire,
when melting, stir about and evaporate to dryness
oaly. This substance, ground in oil, acts as a dryer.
Sugar of lead. ground in oil, is the best dryer for deli-
cate tints. Litharge is the most active dryer of all,
but can only be used for dark colours, as it discolours
light and blue tints. All oxides are dryers, as a
general rule.-THE WELSH SHEPHERD.
[2332]-UNNOTICED QUERY.-The traced pat-like physical theories, and is Irish in reference to
terns for embroidery are printed, when many copies
of the same pattern are wanted. If a dozen or two
are only required, the patterns are made by hand, as
follows:-The drawing is made upon paper, lay the
drawing upon an even cloth, and perforate all the
lines with a fine needle, close and even. Now take
finely powdered charcoal three parts, resin one part in
fine powder, mix and tie it in a piece of porous
calico, so that it forms a dusting bag. Lay the per-
forated drawing upon your material, hold down with
one hand, rub the dusting bag over the drawing, the
dust falls through the holes, and forms the drawing on
the material, remove the paper drawing, lay blotting
paper over the dust pattern, and go over it with a
worm flatting iron; the heat will melt the resin and
fix the drawing on the material.-THE WELSH
SHEPPHERD.

[blocks in formation]

FIG. 4.

8.75

7

all, 15ft.; greatest beam, 2ft. 2in.; depth, less keel,
Din.; rise of deck. 3in. This boat may, with the ex-
ception of ribs, carlins, and risings, be built entirely of
pine, which should be fresh cut from the balk, as it will
then be easier to bend and less liable to split; or if
"Oversands " prefers,
the keel can be made of
oak or American elm,
and the curved stem and
stern pieces of oak, the
ribs of chestnut, steamed
or boiled till soft, to be
fixed hot, as they set
in cooling, and will not
alter in shape when
once in; keel, allowing
for scarphis about 13ft.
long, in. deep, 1fin.
wide, to have a rabbet
worked on each side and
up the curved pieces (as
high as boat is to go),
where the rabbet flat-
tens. Fig. 1, section of
keel midships; Fig. 2,
method of scarphing
cutwater to keel: T
places for screws, which
should be brass; Fig. 3, section of stem (stern is
similar), through a b; Fig. 4, half of main section,

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BETA.

[2362]-COPPER SMELTING. -In answer to E. V. D. S." I am not aware of there being any copper smelting establishment in London.-T. Ros

KELL.

[2363.-SILVERING BRASS.-In answer to " Poor Clock Jobber" respecting silvering brasswork or clock dials, the following is the method used for many years to silver the clock rims or inside bezils:-6d. of pure silver dissolved in half a teacup of nitric acid, the solution of silver to be carefully washed to free it from the acid; afterwards to be mixed with 1d. cream of tartar; when the tartar is mixed add half a brick of cominon table salt, pounded fine, the whole to be well stirred together. The articles to be silvered must be dipped clean in aqua fortis, or scoured with fine sand. The part to be silvered must be rubbed with a clean cork dipped in water, then in the silver powder. The whole to be rinsed in lukewarm water, and dried in clean box sawdust, and then be varnished with copal varnish made thin with turpentine. This is an old method. The modern one is to laquer the work with colourless lacquer.-J. M., Birmingham.

[2380.]-MERCURY BREAK FOR COILS.-" R. S." will find a description of a mercury break in the appendix of "Chambers's Electricity," by Dr. Ferguson. It consists of a vibrating spiral of copper wire. Another form is given in Du Moncel's work on the induction coil as constructed by Gaiffe, which, like the ordinary spring break, derives its motive influence from the core of iron wires. It is constructed; as follows:-A brass pillar with a slot cut in the top carries a lever of soft iron some 6in. long, one end of which terminates in a cylinder like that of the spring break; the other end has a wire depending from it tipped with platinum, which dips into a cup containing an amalgam of mercury and platinum, or mercury and silver (which is cheaper and more easily made); the iron lever is centered in the slot by means of a pin passing through it, so that it can slightly oscillate in the vertical plane; a spring bent is the form of an arc is fixed to the under part of the lever, which, by means of a rack adjustment, can be made more or less tense, so as to accelerate or diminish the rapidity of the oscillations. The pillar is of such a height that the cylinder end of the lever, when at rest, is about fin. or 3-16th in. above the cup is capable of being adjusted to any required height, so that the platinum wire just touches the amalgam; over the amalgam is poured some alcohol, which, being less conductive than air, renders the passage of the extra-current spark more difficult. The pillar and the cup are respectively connected with the coil in the same manner as the two sides of the spring break. This form of contact-breaker is chiefly applicable to the larger class of coils, especially when used with great battery power; as before stated, it renders more difficult the passage of the spark of the extra-current, which so rapidly oxidises the platinium of the spring-break; moreover, for the same reason, it elongates the spark of the secondary wire. In a coil I recently made, the spring-break, with 3 Grove's cells (5in. x Sin. of platinum immersed) gives sparks 6in. long; the mercury break, with same battery power, gives sparks 7in. The mercury break is, however, not adapted for illuminating vacuum tubes.J. D. M.

[2371.] HEATING OF JOURNALS. -If "Rel-end of the bundle of wires in the coil. The mercury
wot" were to remove the brasses from his heating
journals, and replace with hard wood, and state the
result in the pages of the ENGLISH MECHANIC, it
might benefit others as well as himself. It is best, if
possible, for the wood to be endways of the grain. I
was in a very large windmill last week, where the
lower end of the wind-shaft was working against
wood, but in this case, the wood was strongly bound
by an iron band, to prevent splitting, as the pressure
was very great, and brass had been removed on
account of heating; it has been at work thus for many
years. The necks of all the stone spindles in the mill,
four pairs, are working with wood instead of brass in
a satisfactory manner.-R. N. SMITH.

[2371.]-HEATING OF JOURNALS.-" Relwot " should apply clean soft soap, let the neck revolve in this a few moments, then pour on common washing liquor, which will fetch out the dirt. Repeat if neces sary. This can be done without stopping the engine, and has often proved effectual.-MUTUAL IMPROVE

MENT.

[2371.]-HEATED JOURNALS.-Heated journals in many cases may be cooled by pouring a mixture of antimony and oil frequently on the m. VIVIS SPERANDUM.

[2376.]—GEOMETRY.-The following is perhaps the easiest method of solving this rather long problem. First of all determine by its traces (H T and V T the plane inclined 50°, assuming this plane perpendicular to the vertical plane of projection; next determine by its plan and elevation, a perpendicular line to this plane; then a plane containing this line, no matter in what position, must be perpendicular to the given plane. To determine the position of the second plane (70°), make the point 0 (where the line intersects the plane), the apex of a right cone, whose slant edge is inclined at 70. All tangent planes to the slant sides

[2381.]-FIXING IRON STANDARDS IN STONES.in stones for wire fencing, railings, &c., is composed of The composition generally used for fixing iron standards

brimstone (crude sulphur) and washed dry sand in about equal parts, poured into the joint in a molten state.VIVIS SPERANDUM.

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[2384]-WORK ON ELECTRICITY.—I should recommend S. T. P." to purchase either "Noad's Inductorium," price 3s. ed., or "The induction Coil, How Made, and How Used," by Dyer, price 18.-F. RUSSELL.

[2390.]-INDUCTION COIL.-Thomas J. O'Connor may safely use a battery consisting of 6 or 8 Grove's or Buusen cells (pints), or 3 quart bichromate cells.-F. RUSSELL.

[2390.]-INDUCTION COIL.-T. J. O'Connor asks what battery power would be suitable for his coil

the appendix to the "Nautical Almanac" for 1851.If his coil is well insulated, he can use a bichromate HENRY W. HENFREY, M.N.S., &c., &c. battery, presenting a total surface of 48 square inches, [2450.]-FASTENING or one quart Bunsen's battery, with about 66 square PIN TO BROOCH. — In inches. Such a coil with a condenser of 25 sheets, 6 x answer to Yorkshire Bite," he must use shellac to 4, ought to give in. spark at the least.-A. E. TUCKER. fasten the pin or joint in his brooch; this is what the [2399.]-DIE FROM MEDAL.-The best way for black ornament makers use in Birmingham. The joint "Medal " to procure a counterpart or die from his is warmed previously to putting together.-J. M medal would be either to make a mould in plaster of [2455.]-FRET CUTTING ROLLED BRASS. Paris and cast it, or else, which , the better way, to "Chip had better use coarse cut saws to pierce his reproduce it by means of the electrotype process.-F.in. brass with, as the fine ones get hot, and then merely rut, not cut; he must lubricate with a little suet or wax, and not work his saw too quick. I have cut some metal thick, for book mounts, and I found fine cut saws of no use whatever. Perhaps he would let me know how he succeeds in his next attempts?—"J. K.P.'s" letter on another page.-ED. E. M. J. M.

RUSSELL.

T. ROSKELL.

Put

lemon upon 1lb. of refined sugar, not broken. 3oz. of tartaric acid in 2 gallons of cold water, let it stand 12 hours or more, put the sugar which has abup. When sorbed the essence of lemon to it, and stir bottled, add a desert spoonful of carbonate of soda 14 a quart bottle not quite filled.-MINNEHAHA. [2481.]-GUANO INJURIOUS TO HEALTH.Science Gossip, September, 1866, quotes the followin fact from the Gazette de Lausanne:-"A peasant cutting wood was wounded by a splinter, and having afterwards worked in guano, this substance entered the wound and occasioned death by poison after three [2403-FLUXES.-In reply to "Dorset," he can obtain door spar from any of the mining districts of days' suffering."-X. Y. Cornwall. I get mine from Redruth, though one of [2492.) BENNETT'S CHUCK.-For reply see the assayers. It can be had in powder from almost [2499.]-APPARENT ANOMALY.-Edward Haberall drysalters and dealers in chemicals. J. J. Griffin, (2456.1-OLD COINS.-The first-mentioned pieces glam has got fogged by mixing troy and avoirdupois 22, Garrick-street, Covent-garden, London, supplies it: white argol may also be had at the same place. of "Shabazadah," are merely Nuremberg tokens or weight together. Penny weights appear in the former White argol is the commercial name for crude counters, and are of no value. He will find many par- only, which has 12oz. to the pound of 5760 grains. It bitartrate of potassa; cream of tartar is the same, ticulars relating to them in the last volume of the is well worth bearing in mind that though the troy purified; tartaric acid is also obtained from it. It is ENGLISH MECHANIC. see pages 309, 537, &c. The pound is so much smaller than the avoirdupois pound half-of 7000gr., yet the troy ounce has 480gr. against the 437\ chiefly obtained as an incrustation in wine casks.-following is a description of the "Voce Populi pence. Obverse, a laureated head to the right, the that go to the avoirdupois one, for if you go to a sale neck being bare. Legend; VOCE POPULI. Reverse, and buy plate at per ounce, as a friend of mine did, a female seated, looking to the left, holding a branch and get charged by avoirdupois, you will pay about 11 in the right hand; a spear, pointing backwards, is per cent too much. It must also be remembered that the apothecary's drachm is 60gr., and the drachm, as I supported by the left arm, and behind the figure is a harp; HIBERNIA above, and the date, 1760, below. think it should always be spelt, though we do not find There are a great many minor varieties, which I need much distinction made in the dictionaries, is about not notice here. I extract the following from the 27 gr., and is what we talk about when we say we put Numismatic Chronicle:"-" For some years prior to 3dr. of powder into a charge for a small-bore rifle. 1760, very little copper money was struck for Ireland. As regards the weight of water, we commonly see put which caused such a scarcity of small change that all in books that a gallon is 10lb., also that in a cube-foot sorts of base stuff was cast into pieces that passed for there are 6-232 gallons; and should conclude that a halfpence and farthings. This gave an opportunity to cube-foot would weigh 62:321b., whereas we are always a Mr. Roche, of South King-street, Dublin (who struck told it is 624lb. It would reconcile matters, and be metal buttons for the army), to issue copper halfpence just as easy to remember, if it were called 621b., and and farthings, which were generally received in pre- would be nearer the mark a good deal.-J. K. P. ference to the wretched sort then in circulation. The [2501.]-INDUCTION COIL.-T. J. O'Connor's diffifirst sort he sent out was badly finished, and on one side a head laureate, looking to the left, and for in-culty would appear to be that no contact is completed. He must not expect an iron screw and steel spring to scription, VOX POPULI; reverse, Hibernia sitting work to any sort of satisfaction. The metals would on a globe, holding a laurel branch in the right hand be immediately oxidised and rendered non-conducting. and a spear in the left, with HIBERNIA round; in and no doubt this is the case now at the point of the exergue the date, 1760 (none of these sort are now actual contact of screw and spring.-SIGMA. known to exist). The second sort that he issued was much neater, and better copper, with the inscription on the head side altered to VOCE POPULI. The halfpence were a larger size, and done in the same manner. However, on information being given to the then Lord Mayor of Dublin, the whole apparatus for striking the aforesaid coin was seized and lodged in the tholsel. Roche fled from the same." The most comprehensive account of these curious pieces is by C. Clay, M.D., published in Part III. of the "Proceedings of the Manchester Numismatic Society," 1866. The medals in brass of Admiral Vernon, are very commou, not being worth more than 1s. I have two specimens in my cabinet, commemorating the taking of Porto Bello.--QUERCUS. HENRY W. HENFREY, M.N.S., &c., &c., author of a "Guide to English Coins.'

[2404]-TELESCOPE QUERIES.-I am unable to answer the query addressed to me by "C. S.," page 69, for the following reasons. I do not possess an eyepiece of the power he mentions-the highest I have used is about 300; also my telescope was left behind in Manchester, and I fear that I shall not be able to send for it before the middle of June. One point is worthy of notice, the stand seemed almost perfect on quiet nights, but if not sheltered, the instrument had an unpleasant tendency to come "head to wind," so smoothly and easily did it work. This will be remedied when I get to work again, and I think it will then be the best possible form of stand for an altazimuth.ARTHUR W. BLACKLOCK, Newbridge, Aberdeen.

[2407.]-DYEING.-"Mordant" will get the fullest information about chemical dyeing in "Musprat's Chemistry," but it is a very expensive work. Napier's Handbook on Dyeing" may suit him, it is more mechanical (if I may use the expression) dyeing than chemical, but contains a multitude of recipes for dyeing cotton and silk in all colours.-Vivis SPERAN

DUM.

[2414.]-ALGEBRAIC EQUATION. - Let x greater number.. 2 less number, Then

or

or

or

whence

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2) (2x-2) = 12

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(x-3) (x2 + 2) = 0

30 and 2 + 2 = 0 .. 3 or + √ - 2

and the less number = x2=1 Or

=

+ √ 2- - 2 = (√ − 2 − 2) or (√ − 2 + 2) -J.P.P. [2414] ALGEBRAIC EQUATION.-"Pater" will find the following to be a correct solution of his problem:-Let 3r the greater number, and x = the less; then (3.2 x 4r) = 12; or, 12 = 12; dividing by 12. 31; extracting root, r = 1; therefore, 3 = 3 Proof:-3-12, the required difference; (3 × 1) × (3 + 1) = 3 x 4 = 12.-W. AIREY,

[2456.-OLD COINS.-The one figured is a Nuremberg token. The words "Hans Krauwinkel, Nur." are very legible.-BERNARDIN.

[2456.]-OLD COINS.-Is a counter or jetton; made by Hanns Krauwingel, whose name appears on the coin. If Shaazadab will refer to "Snelling's View of the Origin, &c., of Jettons or Counters," or even to the ENGLISH MECHANIC, a few weeks back, he will find all, or as much other information he may require. The Voce Populi," or "Pretender's halfpenny," as it is sometimes called, was struck in Ireland in 1760. [2416.]-ADHESIVE MATERIAL.-A thick mix- It is rather smaller than an ordinary sized halfture of dextrine and water possesses great adhesive- penny of the period. There are conflicting accounts of ness. Dextrine, or British gum, is made by exposing its appearance as a singular and distinct coinage, and potato starch to a temperature of 4000. It is a cheap it is singular that its origin should be lost in obscuarticle, and largely used as a substitute for gum.-rity, considering its comparatively recent date. The various authorities on the subject are brought together and printed in the "Proceedings of the Manchester There is a variety Numismatic Society," Part 3. with the letter P in the front of the bust, and another with P under the bust. There is also a farthing size. The Vernon medal was probably struck on the taking lectors will send information.-D. T. BATTY, Fennellof Porto Bello, and I dare say some of our medal colstreet, Manchester.

BETA.

[2420]-SPRING BOW.-A steel spring bow of given length cannot be weakened except by reducing its substance in thickness, or otherwise.-J. B. [2423.]-AQUARIUM.-Why does not your correspondent use gas piping? I have used it continuously for several years. My fishes lived and got fat, yet never fed them, but kept the aquarium well stocked with vegetation. I have found no cement to surpass Portland cement, it hardens under water, and makes a good artificial stone.-COUNTRY GROCEB.

[2457.]-TEA CHESTS. -I would state that it is my opinion that the chests which come from China and Assam are made from the wood commonly called of China, abounds in forests of this tree.-W. STEPHEN

NOTES AND QUERIES.

[2503.]-TOBACCO FUMES-Cau any reader inform me of the best mode of deodorising a furnished room containing tobaeco fumes ?-R. W.

[2504.]-UNIFORM TEMPERATURE.-How can I keep the temperature of a room, and a tank of water in it, at exactly 50° Fahr., both in winter and summer?

[2505.]-WEIGHT OF WATER. What is the weight of a cubic foot of fresh water and sea water, each at 60° Fahr. ?-QUERCUS.

[2506,]-CAMPHORATED COLZA OIL.-Will C. Ward kindly state what this is, and how prepared? I have a real argand lamp, the cotton in which is raised and lowered by a rack and pinion; it gives an excellent light with sperm oil, but this is far too dear, and the common colza oil will not suit, as it crusts so rapidly, the tubes in the lamp being very close, and the cotton fine. Possibly the camphorated colza oil mentioned by Mr. C. Ward might suit.-S. J. M., Peuge.

[2507.)-RECOVERING GOLD.-I see in last week's ENGLISH MECHANIC a plan to recover the silver off of plated ware without dissolving either copper, brass, or German silver, which I consider very useful. Can you or any reader of the MECHANIC give the same for recovering gold off plated ware, and also how to recover the gold afterwards in the metallic state, as thick on the metal that they are made of, which I have some old spoons that have been gilt pretty looks like copper?-T. E. D.

[2508] FASTENING STENCIL COLOURS ON PAPER-Can any brother reader inform me of any method of fastening stencil colours on paper that will size and varnish. I have tried vinegar and alum to fasten the ordinary pigments that are ground for paint, but they won't stand the size. I have used stiff but it is apt to make greasy and unclean work?PAINTER.

[2423.]-AQUARIUM.-Gutta-percha does not affect here Indian teak. The country round Assam, south colour ground in oil and well diluted with turpentine,

nated with it.-J. B.

water in any respect, neither fish or any other thing
will be therefore injured by water which has passed
along pipes of that material, Roman and Portland
cement are suitable for uniting rock work, and can be
obiained by any mason; but both of these, and the
former especially, give off an efflorescence for a time,
which is poisonous to fish if the water gets impreg-
[2424.]— MICROSCOPICAL- The Quekett Club
publishes a quarterly journal, which is supplied to its
members free of charge, and which contains reports of
the proceedings of the club, and in which the most
important of the papers read at the meetings are pub-
lished in full, with illustrations, when required. A
member unable to attend the meetings could scarcely
derive any advantage beyond the perusal of the jour-
Dal; but any subject he might wish to bring under the
notice of the club, with a view to elicit opinions, or
otherwise, would receive attention if brought forward
through the secretary or any other member. As a
regular attendant at the meetings of the club, I should
be glad to be of service in this way to any absent
member. Nelson's gelatine is largely used, and can
be had, I believe, of almost any grocer. With Cox's
I am not acquainted, nor have I ever known isinglass
to be used for microscopical purposes.-W. H. G.
(2489.1-SLOT CUTTING.-See "J. K. P's" letter

elsewhere.-ED. E. M.

[2442.] MOUNTING LARGE CYLINDER. "Woodleigh" had better have wooden caps to fit the ends of his cylinder, with brass bearings screw tight in the centre of the caps, and secured by a lock-nut inside and varnished with sealing wax varnish. I have one that is done the same way, aud it answers well.-J. M.

[2448.)-PLANET NEPTUNE.-Adams's calculations and formula first appeared as an extract from

SON.

[2509.]-PUMPS.-Many thanks to "C. S." for his private answer to my inquiry about the turbine wheel. see that it will not do. I would like to know what would be the most advisable plan for to send up about 4000 gallons of water in the shortest time; driving power, 8ft. of a fall, and 50 gallons per minute? In reply to "H. B. M." There has been a ram tried already and found to be insufficient.-PLUMBER.

[2459]-BANKAL WOOD.-Bankal wood, of the
Philippine Islands, is the wood of Nauclea Glaberrima,
of the Peruvian bark order, or Rubiaceae; this wood, of
a golden or a greenish yellow, is esteemed for its
tenacity and durability, is employed by shipbuilders,
coopers, &c.; it is abundant in the Philippine Islands.
For more particulars on the woods of these islands,
see my notes in the Technologist, August, 1864
Some other trees of the Genus Nauclea yield also a good [2510.]-PEPPER MOTH.-TO MR. CLIFFORD.-
timber:-In Senegal, the Koos, Nauclea Africana; in I should esteem it a favour if our friend who writes
Tahiti, the yellow wood of N. rotundifolia, hard, and us those interesting monthly chapters on curious cat-
excellent for carpentry purposes; in Ceylon, N. Coadu-terpillars, or some other brother reader, would favour
nata, Roxb., the Bakmee-gaha of the Singalese, light
and tough, used for doors, &c.; N. cadamba, Halamba
of the natives, and N. cordifolia, both used for building
purposes; in Java, N. lanceolata; Angriet, Malay,
brown, hard timber, very difficult for working, never-
theless employed by wheelwrights; and N. purpurea,
or Tjangtjaratan, light, with rather loose fine fibres,
working easily, but having no special use,-BERNAR-

[blocks in formation]

me with an answer. What colour is the larva of the pepper moth (Amphydasis betularia), and what position found in when feeding; also what it feeds on, and what localities are the most suitable to it? What time of the year does it make its appearance ?-PUPA.

[2511.]-BEER.-Would you or some brother reader inform me of a book treating on the benefit to be derived from the moderate use of intoxicating drinks as beverages?-A. L. E.

rived from moderate drinking have been written on [We know of no such work, though the benefits deand spoken on again and again. It is, however, our opinion, grounded on a long experience and much observation and inquiry, that the benefits derivable from the habitual use of alcoholic beverages are very small indeed. We do not say this from a teetotal point of view, but as ordinary observers of the habits of men. We have known hundreds of men, some of whom were miners and sailors in Cornwall, spinners in Manchester, agriculturists in Devonshire, and printers in London, who have abstained for years together from all kinds of intoxicating drinks, and then we have known hundreds of others similarly

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