rows of wild chesnuts, have been set apart for the scholars' recreations. It was opened on the 23rd of October last⚫ -Quarterly Journal of Education.

FASTENING SKATES.

Sir,-As I feel the inconvenience arising from the present mode of fastening on skates to one fond of the amusement, I beg leave to send the following plan for the consideration of your readers. Suppose, that instead of a screw, as is generally used, there were a rim of iron raised round the heel of the skate so as to fit to the heel of the shoe, and in it a square hole to admit a plug, such as is used to fill up the hole in the heels of boots when the spur is removed. This would not only not require the time that the common heel-strap demands, but hold it on faster; and, instead of a strap over the toe, suppose a toe-piece, such as French clogs are fastened with, were substituted,

no

more trouble would be required than to slip the foot into the skate and push the plug in. This plan would prevent that unpleasant cramping of the feet which a number of straps tightly bound over it causes, and would greatly add to the comfort of the skater.

Mr. Pepys, in the Poultry, has invented a sort of skate to fasten on quicker; but, unhappily, they unite immense expense with utility.

Yours, &c.

AN OLD SKATER.

SUBSTITUTION OF MECHANICAL FOR ANIMAL POWER.

Sir,-In consequence of your note appended to my last letter, I beg leave to say, that I have your opinion inserted (No. 325) in support of "the application of mechanics to political economy." Dr. Goldsmith, and all natural historians, inform us, that "to decrease the number of animals, and increase that of vegetables, has been the general scope of human industry." Hezron and Saxula are labouring to conquer from 2,000,000 horses the territory for 16,000,000 men, women, and children. We shall yet, I trust, live to see all the advocates of emigration walking captives after Saxula's triumphal car!

With the advice of M. Say, the French import foreign cattle, while the ports of England are, one and all, closed to the importation of foreign cattle, though open without ion to the exportation of of her population.

the 1

Steam-worked Paddles.-Mr. Editor, Having read, in Nos. 429 and 433, of your Magazine, those articles respecting paddles worked by sails, I beg to offer some remarks upon them, with the hope of drawing the attention to them of those persons who have been, or are, making experiments in order to obtain that desirable object of making a vessel sail directly in the "wind's eye;" which, to say the least of it, as one of curiosity, would be of equal importance to nautical science as the discovery of the North Pole would be to geography. The idea of propelling vessels by windmills is by no means new; therefore, those who may have recently revived it in their imagination, would be furthering science more by giving up their claim to priority of invention, and exerting themselves to prove practically whether a vessel can be propelled against the wind by such means; and whether she will make more way to wind. ward than a fast-sailing, "fore and-aft" rigged ves sel would. I confess my opinion is, that she would not; and I even doubt, that under the most favourable circumstances of smooth water and velocity of wind, she would take any way whatever in the wind's eye, wuile in any other direction she would move slower than the vessel with, common sails; certainly, all the plans or models which I have seen or heard described would fail. I conceive your excellent Magazine to be a good medium for removing what may be prejudiced doubts or misgivings, and I shall be very glad if mine in the present instance shall be proved to be of this description. Perhaps the owner of the model, which was exhibited at the Admiralty, may contribute some inportant information upon the point. Or, as your Magazine is generally read on the other side of the Atlantic, the American who wrote in the newspapers about five years since upon windmill-sails as applied to vessels, will probably be so obliging as to inform your English readers how they competed with the steam vessels upon the magnificent rivers of the United States in a fresh breeze. Or, the Chinese, who have for ages past propelled land-boats by horizontal windmills, may, if questioned, inform some Captain or Officer of one of the Hon. Company's ships the rate of their velocity when sailing head to wind, with all the advantage of terra firma to hold on by, instead of a piece of board in a yielding fluid.-Yours, &c., H. M. Dec. 26, 1832.

INTERIM NOTICES.

We thank" Octavius," and W. A. M'K. for their friendly observations, and to a certain extent admit the force of them.

The reply of Junius Redivivus is unavoidably deferred

Communications received from Trebor ValentineMr. Busby-Mr. Ryan-Mr. Ralph Dixon-A. B. T. C. D.-Mr. Baddeley-Humanitas-Wm. B.Mr. Williamson-A, C. F. T.-Mr. FullerHydraulic,

LONDON: Published by M. SALMON, at the Mechanics' Magazine Office, Wine-Office-court, (between 145 and 146) Fleet Street, where Communications (post paid) are requested to be addressed. Sold by G. G. BENNIS, 55, Rue Neuve, St. Augustin, Paris. GRAY and BOWEN, Boston (US

M. SALMON Printer, Fleet Street.

Peterhoff Paper Mill, near St. Petersburgh, August 23, 1831.

reams are put in and taken out. When the paper is in its place, the under or counter nuts are run down an inch or so; the upper nuts, which are six-sided, are

I shall begin with first describing the principal working parts of the machine. Two riggers A (see opposite page) are driven from below off one of the engine-woolers; and on the shaft there is a sliding clutch-box with a lever, marked B, for instantly stopping or starting the machine. From one of the riggers a strap proceeds, which sets in motion the rigger C, with a fly-wheel and arm D, which being connected with the head with the knife, or cutter E, causes it to slide along the bar F, which is of a triangular form, as represented in the section F'. G is a handle, by turning which, with the help of two pair of mitre-wheels, fixed on a shaft, and the vertical screws attached to the bar F the knife-bar, &c., is made to descend. The mode of operating is as follows:-On the machine-table or platform we place each ream on its beechboard, for the ploughing-knife E to cut down to. We then lay on a sheet-brass gauge plate, and mark off with a pencil how much of the three external sides are to be cut away. The paper is then put on the machine, which has a sort of parallel ruler back, worked by two pinions and racks. The handle H is now turned towards the workman, and the pencil-mark brought level with the front of a double iron straight-edge. The lower edge is fixed firm and level with the table; and at each end there is a 1 inch cylindrical pin cut, with a double-screw (for dispatch) and two brass nuts, of which the lower one is round, and works slack, being intended merely to hol

upper straight edge while the

ners, on the five reams of paper, care being taken to screw both ends of the iron straight-edge down at one time. The lads broke three cast-iron straight-edges before they got well used to the machine, by not screwing down equally. The last one I backed with two half-inch bars, clamped on edgewise, and it has lasted years. It sometimes happened that one ream of paper was rather thicker than the others; but by slackening the bar, and putting two or three sheets of paper on the thin ream, the inequality was easily remedied; now such a thing sel dom occurs. After one face has been thus ploughed, the clutch is detached by the lever B, and the handle G being quickly turned the reverse way, brings up the bar with the knife or cutter E. The upper nuts are then slackened, and the parallel back, by moving the handle H as required; after which the reams are turned, and again brought up to the straight edge.

The table and sliding-back are made of mahogany, the frame I of fir. The frame which carries the fly-wheel and rigger C, &c., is of cast-iron, and square at top and bottom, with four hollow fluted columns. The guide-wheel, mitre-wheels, and the sliding parts at the end of the bar and head, are of brass kept clean. The ploughing-knives, when new, are 10 inches long, 2 inches wide, and 3-8ths thick, requiring to be very flat on the face, and stiff. I make them of English cast steel; and when worn down to about 7 inches, they are considered as having done their duty, and are then worked up into other tools. Four or five will last a year. It may be proper to add, that the post or frame marked X reaches from the floor to the ceiling, for carrying the shaft, fly, and riggers A, and that the other end is fixed on an iron cradle. The knife makes 25 double strokes per minute of 4 feet 6 inches; if the machine worked quicker, it would

heat the knife.

I take the opportunity of also sending you a description of a machine for stamping the paper at the corner, in three or six sheets at a time, which is worked in connection with the ploughing-appara

press is, that by one turn of the crank it makes 2 blows or impressions 50 times per minute. We before used a small handpress, but this is more expeditious, and saves a man, which is an object where men are scarce. In all parts of this machine, the axle and bolts are two inches thick were they smaller, the great strain would soon make them slack in the joints. The bed-pieces are pewter or grain-tin, 3 inches square, and 1 inch thick, cast with a pin on them, thus,

SPORTSMAN'S SAFETY CHARGER. Sir,-The frequent accidents which occur in using large guns for wild fowl shooting, from particles of wadding remaining after the discharge, induced me to consider some means of providing against such occurrences, and I have invented a very simple kind of safety charge, a rough sketch of which I inclose, and if you think it worth your notice, you are welcome to place it in your valuable Magazine, for the inforination of "gunners."

There is another advantage in the use of this charge, and which, I think, an important one, viz. that of delivering the powder directly into the chamber of the breech, without leaving any of the loose powder, on the sides of the barrel, as is the case when loading in the usual way, if the weather be damp or the barrel foul; the objection to this requires no explanation, as it must be obvious to every sportsman. My method of loading is as expeditious as any other, and I have myself experienced the benefit of the contrivance. Yours, &c.

A SUBSCRIBER AND INDIAN
CORRESPONDENT.

Allahabad, April, 1831,

Description of a Safety-charger adapted to Colonel Hawker's Staunchion Gun (Vide, Plate VIII. of Col. H.'s work, 1825.)

The charger consists of a tin or brass tube, of the form represented in the accompanying sectional sketches, and made so as to slide easily down the barrel. A is a solid valve plug, and a a its socket; B, a piece of cord attached to the valve A. A full charge of powder reaches to about the point e e The gun

is held horizontally when the charger is introduced; it is then suddenly elevated, when the charger runs down, and the yaive-plug A striking the chamber of the breech rises out of its socket (as shown in fig. 4); by pulling the cord B with a slight jerk, the valve is raised as far as C, and the powder entirely delivered, after which the charger is withdrawn.

TRIANGULAR FIGURES-SEPTENARY

SYSTEM.

Sir-In order to direct the more particular attention of your readers to a law belonging to the first division of the Sept. Syst. I may be permitted to refer to the famous proposition of Pythagoras, that "In any right-angled triangle, the square which is described upon the side, subtending the right angle, is equal to the squares described upon the sides which contain the right angle."

A no less important proposition is, that "if the hypothenuse of any rightangled triangle be the diameter of a circle, the right angle will be in the circumference."

Now, neither of these properties of the right-angled triangle, I beg to submit, is more remarkable than its application to determine the adjustments of the double crank apparatus to describe certain

curves.

1st.-Let C and D, the extremities of

* Figs. 3 and 4, front page.