at the top; at what distance from the root must it be cross-cut, so that the cubic contents of the two sections will be equal?

3. When the full moon is near the meridian altitude, if you ask the question at several persons what apparent diameter she appears to them to be, you will rarely find two that will agree on that point; nay, so widely do they differ, that I have found the moon's apparent diameter to extend from a crown piece to the end of a hogshead. Could any of your numerous and intelligent Correspondents assign the cause of this curious fact; or is there any specific apparent diameter the moon ought to present to our vision from her known size and distance from the earth?

I am, SIR, your's, &c.

Hamilton, October 5, 1824.

G. B.

A METHOD OF HARDENING
WOOD FOR PULLEYS.

After finishing the pulley, boil it seven or eight minutes in olive oil, and it will become as hard as copper.-J. R.

METHOD OF OBTAINING SKELE-
TONS OF MICE, FROGS, &c.

If a mouse or a frog, or other like
animal, be placed in an ant-hill, it will
be devoured in a few days to the bones
and ligaments. Hence we are furnished
with a method of obtaining skeletons of
those animals, exquisitely beautiful, and
perfect, and far surpassing any thing that
can be executed by artificial anatomy.
The subject for this purpose is to be en-
closed in a wooden box, and properly
distended, to prevent the parts from col-
lapsing or being crushed together by the
earth. The box is to be perforated with
a number of holes, through which the
insects will presently find their way.
J. R.

GLASGOW GAS-WORKMEN'S INSTITUTION.

"Whence is this power, this foundress of all arts,
Serving, adorning life, through all its parts,

Which names impos'd, by letters mark'd those names,
Adjusted properly by legal claims,

From woods and wilds collected rude mankind,

And cities, laws, and governments designed?

What can this be, but some bright ray from heaven,

Some emanation from Omniscience given?"-Jennyns.

SIR,It is gratifying to the philanthropic mind to contemplate the many opportunities afforded in our public institutions to the artizan, to obtain an intimate knowledge of those principles of science which are essential to the arts and manufactures. There are, how

ever, many operatives without the boundary of these privileges, and it may not be uninteresting to some of these to hear of the existence of a society of minor extent having the same end in view, though with limited means, but with the most satisfactory effects resulting from its operations. Such associations are worthy of being imitated by our friends in the country and it certainly would be enlightened policy in the proprietors of works and manufactories to give every encouragement and facility to their operatives in establishing institutions of the kind alluded to, where the mind may be improved and instructed in the principles of science and philosophy-circumstances which may ultimately prove a powerful antidote to those habits of a demoralizing tendency so frequently to be met with in most public establishments.

The society to which I allude, is composed, exclusively, of the workmen employed at the Glasgow Gas Company's Works. About three years ago, Mr. Nelson, the Manager of the Works, with that benevolent spirit for which he is distinguished, suggested to the workmen the great advantage which would accrue to themselves, should they establish a library for their mutual improvement. Several of the workmen immediately adopted the suggestion, formed themselves into a society, and framed proper regulations to be observed by its members. Every encouragement was given to these laudable efforts an appropriate library-room was granted them, and, with the assistance of a few donations of books, their library at the present time has accumulated to upwards of 300 volumes.

At the beginning of the present year, the Directors of the Company observing the great benefit which had already resulted to the workmen from these arrangements, and desirous

192

THE GLASGOW MECHANICS' MAGAZINE.

of rendering their mode of instruction still more efficient and interesting, and of affording greater facilities for the acquirement of knowledge, with a liberality which does them the highest honour, gave orders that a hall should be fitted up, where the members might conveniently meet to transact the business of the library, and other affairs of the miniature institution, to communicate mutual information, and to make experiments in Chemistry and Mechanical Philosophy.. In the prosecution of these views, by their own exertions, and the kind assistance of their friends, the society has now a considerable chemical apparatus in their laboratory, as well as several very valuable and useful apparatus for the illustration of the various branches of science. At the present time, they have meetings twice-a-week, in the evenings, for the above purposes, when one of their own committee alternately officiates, and gives a short explanation, or rationale, of the several experiments performed. And, although a luminous train of theoretical reasoning is not here to be expected, yet it shows considerable perseverance and success among the inembers of their committee, who have improved these privileges so much, as to excite the regular attendance of almost the whole of the members every evening, and to produce among them the greatest attention and decorum, while they observe with becoming interest the result of the processes laid before them. The whole number of workmen permanently employed about the Works are from 50 to 60 men, of which about a dozen only are mechanics, the rest being operatives; of this total, from 42 to 44 have joined the society. They pay a small sum at entry, and a small weekly or fortnightly contribution; which, together with the fines, are the only support of the institution for extending the library and apparatus, and for defraying the expense of experiments. The entry-money is always repaid to any member on leaving the Work.

Thus, a few individuals, under the auspices of their employers, by a small weekly contribution, (which to each in a whole year would scarcely amount to what some of our operatives spend in an evening in a tap-room,) have established an institution, as honourable to their good sense, as it will be profitable to themselves in the acquirement of useful knowledge; and while they are thus edifying their minds, they are insensibly acquiring habits of useful industry and perseverance-habits which bear a wonderful contrast to those which mark the numberless misspent hours of too many in similar conditions of life.

So striking to the truly philanthropic mind is the consideration of the effects of this institution, that a very worthy and learned Judge, who is an ornament to the highest court in the country, condescended to visit its humble walls, and to pass his unqualified eulogium, both on the object of the society, and the manner of putting it into execution; viewing, no doubt, with an eye of expanded intellect, the time when man shall no longer oppress man, but all shall unite in the universal diffusion and enjoyment of that knowledge and liberal feeling which is the true end of his existence.

Should this short detail in any degree stimulate either masters or men to exert their influence in their respective situations, for the formation of similar societies, the object of the writer will be gained.

October 5th, 1824.

I am, SIR, your's, &c.

K.

NOTICES TO CORRESPONDENTS.

C. North's (Wakefield,) NEW COPYING PRESS, will be inserted.-J. F. will see that he is considerably superseded in last Number, and of course excuse us; what we referred to in the Hoop Problem was its being written with pencil; why does he not use pen and ink? We cannot be troubled to read it, because it is scarcely legible.-Rusticus is right; we meant the fourth question instead of the third.-J. P. need not be in such a pet; we did not accuse him of the emulation he seems anxious to avoid, but which we would be sorry he would lose, as we value his correspondence highly; at the same time, as he well knows, we must be allowed to take our own time and manner of insertion.P. Q. will be inserted next week.

Communications from intelligent Mechanics will be very acceptable, in whatever style they may be written, and Original Patents, Inventions, &c. will be inserted on the shortest notice.

Published every Saturday, by W. R. M'PHUN, 155, Trongate, Glasgow, to whom Communications (post paid) must be addressed; may be had also of STEUART & PANTON, Cheapside, London; and EDWARD WEST & Co. Edinburgh.

J. CURLL, PRINTER.

MECHANICS' MAGAZINE.

No. XLII.

"Fire and water are good servants, but bad masters."-Old Proverb.

Saturday, 16th October, 1824.

Price 3d,

NEW FIRE ENGINE AND ESCAPE,
Invented by Mr. WALTER BALLANTYNE, Water of Leith.

MR. EDITOR,-I submit to your consideration the enclosed drawing of a new Fire Engine and Escape, which, for the good of the public, I hope you will insert in your useful Magazine.

DESCRIPTION OF THE FIRE
ENGINE.

A, A, is the Fire or Force Engine. The levers f, f, and g, g, (fig. 1;) turn the cranks c, d, by means of the connecting rods a, b; working at right angles, and giving rotatory motion to the axles and internal cranks s, t, (figs. 2 and 3,) which alternately lift and depress the boxes or pistons h, i.

The two end views, (figs. 2 and 3,) show the situation of the internal cranks and their connections, as they stand when in operation, the one crank being behind the other. The external cranks stand at right angles to each other. The two between the space in figs. 2 and 3, (not shown,) operate in the same manner as a, b, in figs. 1, 2 and 3. The levers f, g, are attached to the connecting rods as at a, in fig. 1, to a in fig. 2; and at 9 in fig. I, to b in fig. 3; which will then have the appearance shown at a, b, on lever f, in fig. 1.

Owing to the situation of lever f the pistons are shown on the half rise and descent, and that of the cranks s, t, (figs. 2 and 3,) shows their greatest rise and descent.

The parallel motion of the piston rods, is effected by the friction rollers k, k, fixed in the iron standard through which they pass, connected to the cranks s, t, by the shears u, v, (in figs. 2 and 3,) to the top of the piston rod j; where the shears are joined by a bolt through both, taking in the iron standard as at w, in fig. 3.

When the engine is not at work,

or is to be taken through a narrow passage, the levers ƒ and g, and the winches x, y, are to be detached at e, e, and put into the engine carriage; it will then pass through a passage of 2 feet with ease.

At the extremities of the levers f, g, there is a hole into which a round handle of 2 feet in length must be inserted, to enable the men to work the engine.

The boxes are much the same as in all other pumps, except that the box i, has a strong division in the centre, through which its rod passes, and is made fast underneath with a

screw-nut.

The rod of the under box passes through the centre of the upper, at which there is a piece of leather placed in a particular manner, to make it water-tight.

The valves are hinged to each side of the centre piece, over which there is a cover of leather. The under part of the valve is also surrounded with leather, to make it as tight as possible.

B, is the service-carriage; r, its pole or drag. The pole of the engine A, A, is omitted, being well understood.

tt, the service or suction pipe; mmm, the force pipe, from the engine to the mouth of the director, at the top of the fire-scaffold.

I have given the scaffold and ladders, simply to show their connection, though not laid down in proportion.

The engine is to be wrought by 8 men at the levers, and 6 at the winches.

DESCRIPTION OF THE FIRE
ESCAPE.

The ladders A, B, C, (fig. 4,) are placed together in the form of a triangular pyramid, and fastened at top by means of a square block of

SKETCH OF THE HISTORY OF PHILOSOPHY, Particularly with reference to Mathematical and Mechanical Science. (Continued from page 167, Vol. II.)