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ashes of John Napier of Merchiston, celebrated inventor of Logarithms, were sited. It is said, in the account given is life and writings by the Earl of han and Dr. Minto, that he was ined in the Cathedral Church of St. es at Edinburgh, on the east side of its hern entrance, where there formerly a stone tablet on the wall, (on the outof the Church,) intimating that the ial place of the Napiers was in that ce. **

Probably this has been stated on authority of Maitland, who, in his story of Edinburgh, says the same thing, who may have supposed that the rens of this celebrated man must have n deposited in the family burial-place, ough there be no visible memorial that s was actually the case. There is rea, however, to believe that Maitland's ement is wrong, and that Napier was interred in the Church or buryingund of St. Giles, but in the Church of Cuthbert's, or, as it is commonly called, West Church; for, in a treatise on igonometry, from the pen of a Scotch Maematician, James Hume of Godscroft, ensed in April 1635, and printed in the lowing year at Paris, we find the follow.. curious passage: "L'inuenteur (de Lorithmes) estoit vn Seigneur de grande conion, et duquel la posterite est auiourd'huy possession de grandes dignitez dans le oyaume, qui estant sur l'aage, et grandeent trauaille des gouttes ne pouuoit faire tre chose que de s'adonner aux sciences, principalement aux Mathématiques et a Logistique, a quoy il se plaisoit infinient, et auec estrange peine, a construict 8 Tables des Logarymes imprimees a dimbourg en l'an 1614, qui tout aussist donnerent vn estonnement a tous les [athematiciens de l'Europe, et emporteret sieur Bigges (Briggs) Professeur a Oxrd d'Angleterre en Escosse, pour apprene de luy cette admirable inuention, de onstruire vne nouuelle espece de logaryme, y laissa ceste charge pour les faire apres mort, ce qu'il fit comme on les voit auiIrd'huy par toutes les boutiques de Libires: Il mourut l'an 1616. et fut enterre ors la porte Occidentale d'Edinbourg, ans l'Eglise de Sainct Cudbert."-Noing can be more distinct than this plain tatement of facts; so that, when we conider how near the period in which Hume's ook appeared was to the time when Naier died, and that he probably had good

*This stone was removed when the row of ouses called the Luckenbooths was taken down; is now within the church.

means of knowing every thing remarkable about this illustrious man, we are led to believe that his account is correct, and that Napier was buried "without the West Port of Edinburgh, in the Church of St. Cuthbert's."

Philosophy.-Write filosophy or philosophy as you please, but agree that as soon as it appears it is persecuted. Dogs to whom you present an aliment for which they have no taste, bite you. You will say that I repeat myself: but we must an hundred times remind mankind, that the holy conclave condemned Galileo, and that the pedants who declared all the good citizens excommunicated who should submit to the great Henry IV. were the same who condemned the only truths which could be found in the works of Descartes All the spaniels of the theological kennel bark at one another, and all together at De Thou, La Mothe, Le Vayer, and Bayle. What nonsense has been written by little Celtic scholars against the wise Locke! These Celts say that Cæsar, Cicero, Seneca, Pliny, and Marcus Aurelius, might be philosophers, but that philosophy is not permitted among the Celts. We answer, that it is permitted and very useful among the French; that nothing has done more good to the English; and that it is time to exterminate barbarity. You reply, that that will never come to pass. No; with the uninformed and foolish it will not; but with honest people the affair is soon concluded. Voltaire.

Limits of the Human Mind.-Newton was one day asked, why he stepped forward when he was so inclined; and from what cause his arm and his hand obeyed his will? He honestly replied, that he knew nothing about the matter. But at least, said they to him, you who are so well acquainted with the gravitation of planets, will tell us why they turn one way sooner than another? Newton still avowed his ignorance.

Those who teach, that the ocean was salted for fear it should corrupt, and that the tides were created to conduct our ships into port, were a little ashamed when told that the Mediterranean has ports and no tide. Muschemdrock himself has fallen into this error.

Who has ever been able to determine precisely how a billet of wood is changed into red hot charcoal, and by what mechanism lime is heated by cold water?

The first motion of the heart in animals -is that accounted for? Has it been ex

actly discovered how the business of generation is arranged? Has any one divined the cause of sensation, ideas, and memory? We know no more of the essence of matter than the children who touch its superficies.

Who will instruct us in the mechanism by which the grain of corn, which we cast into the earth, disposes itself to produce a stalk surmounted with an ear; or why the sun produces an apple on one tree and a chesnut on the next to it? Many doctors have said, what know I not? Montaigne said, what know I?

Unbending decider! pedagogue in phrases! furred reasoner! thou inquirest after the limits of the human mind:-they are at the end of thy nose.— -Voltaire.

Influence of Copper, &c. on Magnetic Needles.-M. Arago has communicated to the Academy of Sciences his further experiments relative to the oscillations of a magnetic needle surrounded by different substances. He had ascertained that the copper rings with which dipping needles are generally surrounded, exerted on the needles a very singular action, the effect of which was rapidly to diminish the amplitude of the oscillations without sensibly altering their duration. Thus, when a horizontal needle suspended in a ring of wood by a thread without tension, was moved 450 from its natural position, and left to itself, it made 145 oscillations before, the amplitude was reduced to 10o. In a ring of copper, the amplitude diminished so rapidly that the same needle, removed 45° from its natural position, only oscillated 33 times before the arc was reduced to 100. In another ring of copper, of less weight, the number of oscillations between the arcs of 45° and 10° were 66. The time of the oscillations appeared to be the same in all the rings. In the ring of wood, 145 oscillations from 45° to 10o. In the ring of copper, 33 oscillations from 45° to 10o. In a lighter copper ring, 66 oscillations from 45° to 10°o.

New Metal.-A new metallic composition has lately been invented by Dr. Geitner, an able chemist in Saxony, the properties of which closely resemble those of silver. It is malleable, is not subject to rust, and is not liable to become tarnished. This composition has already been made use of in the manufacture of candlesticks, spurs, &c. and will in all probability (according to some of the foreign scientific journals) be converted into a substitute for plated goods.

New Comet.-Mr. Gambard of Marseilles, discovered a new comet on the 19th of May, though a distinct observation was not got till the 27th, at Paris. It is near Gamma, in Cassiopeia, invisible to the naked eye, without tail or apparent nucleus, having the form of nebula, which is easily distinguished, notwithstanding the light of

the moon.

Permanency of Human Hair.-M. Pictet has lately made a comparison between a recent human hair and those from the head of a mummy from the Isle of Teneriffe; with respect to the constancy of those properties which render hair important as a hygrometic substance. For this purpose, hygrometers, constructed according to Saussure's principles, were made, one with a recent hair, and the other with hair from the mummy. The ancient hairs were not so strong as the other, or of sufficient length alone, but the latter objection was obviated by tying four together. results of the experiments were, that in both instruments, the interval between extremes of moisture and the dryness of the chamber (about 25°) was passed in three minutes that the indications, like those of the thermometer, &c. were rapid on leaving the first term, and became slower on approaching the second: that the hygrometric quality of the Guanche hair is sensibly the same as that of the recent hair.-Bib. Univ. xxvii. 120.

The

NOTICES TO CORRESPONDENTS.

Z. Z. Z., G. M., D. R., &c. &c. have been received. We should like to hear again from G. Scott, Hawick: his letter will appear next week.

ERRATA IN No. LXXXII.

Page 380, col. 2, line 24, for self-floating read self-fluting.

Page 384, col. 1, line 38, in a few copies only, for neutralized, read naturalized.

Published every Saturday, by W. R. M‘PHUN, 155, Trongate, Glasgow, to whom Communications (post paid) must be addressed.

CURLL, PRINTER.

MECHANICS' MAGAZINE,

CONDUCTED BY

A Committee of Civil Engineers and Practical Mechanics.

"He that enlarges his curiosity after the works of nature, demonstrably multiplies his

No. LXXXIV.

inlets to human happiness."

Saturday, 30th July, 1825.

Price 3d.

MR. CARTWRIGHT'S STEAM ENGINE; PLAN FOR RAISING
COAL BY A WATER-WHEEL.

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MR. CARTWRIGHT'S STEAM ENGINE.

Ir may, we think, prove very advantageous, when we can spare a part of our plate, to extract from some of the old volumes of the different Journals of Science to which the generality of our readers may not have ready access, a few of the improvements and inventions which are there recorded; for even where such have been found by experience not altogether to meet the sanguine views of the projectors, they may contain hints which may be of the greatest importance to intelligent mechanics. With this view we present our readers this week with an account of Mr. Cartwright's steam engine. Mr. Cartwright's first objects were to obtain, as nearly as might be, an absolute vacuum; which, in consequence of the elastic vapour that separates from water injected in the usual mode of condensation, no one in the least conversant with the philosophy of the steam engine, need be told is impossible. The condensation in Mr. Cartwright's engine is performed by the application of cold to the external surface of the vessel containing he steam. This plan had been tried by severals without success, previous to Mr. Cartwright's attempt; his plan was by admitting the steam between the metal cylinders lying one within the other, and having cold water flowing through the inner one, and inclosing the outer one. By this means a very thin body of steam is exposed to the greatest possible surface. But besides this, by means of a valve in the piston, there is a constant communication at all times between the condenser and the cylinder, either above or below the piston, so that whether it ascends or descends, the condensation is always taking place. To reduce the friction of the piston, which, when fresh

packed in the common way lays a very heavy load upon the engine, Mr. Cartwright made the packing of his solely of metal, and expansive. There is a farther advantage in this method from the saving of time and expense in the packing, and from the piston fitting more accurately, if possible, the more it is worked. He was equally attentive in simplifying all the other parts of the engine; his engine having only two valves, and those as nearly self-acting as may be.

He had also another curious object in view in his improvements, which was to afford an opportunity of substituting ardent spirits, either wholly or in part, in place of water, for working the engine. For, as the fluid with which it is worked is made to circulate through the engine without mixture or diminution, the using alcohol, after the first supply, could be attended with little or no expense. On the contrary, the advantage would be great, probably equal to the saving of half the fuel. When, indeed, the engine was applied as he proposed, it occasionally should work both as a mechanical power and as a still, at the same time, the whole fuel would be saved.

Description of the Plate.

A, (fig. 1,) the cylinder; B, the piston; I, the pipe which conducts the steam to C, the condenser, being a double cylinder, between which the steam passes into the pump, D, that serves for returning the condensed fluid back into the boiler; E, the air-box, and e, its valve.

Note. The pipe from the pump, through which the condensed fluid is returned into the boiler, passes through the air-box. What air or elastic vapour may be mixed with

the fluid, rises in the box till the ball that keeps the valve shut falls and suffers it to escape.

F, the steam valve; G, the piston valve; H, H, two cranks upon whose axles are two equal wheels working in each other, for the purpose of giving a rectilinear direction to the piston-rod; M, the box that contains the condensing water;

K, plan of the piston, showing the metal rings, which, by the springs L, L, are forced outwardly against the inside of the cylinder, so that the piston can adapt itself to any inequality that may arise.

The

piston-rod is also made steam tight in the same manner at N; O, a part of the fly-wheel which regulates the motion.

PLAN FOR RAISING COAL BY A WATER-WHEEL.

GENTLEMEN, I was lately asked if I had seen any machines for raising coal turned by water, said to be in use in this country, even in this neighbourhood. I have not; but as I have few opportunities of seeing works of that kind, there may be such unknown to me. It had, however, the effect of turning my mind to the subject, and the following are a sketch of two plans I conceived, which it may be somewhat curious to compare with those already in existence, if such there be; at least I think it a little interesting to compare the ideas of different persons on the same subject, especially if ignorant of each other's designs.

A, B, (fig. 2,) is a common water wheel; A, the trough, or watercourse; C, a wheel, on the same axis which turns another wheel, D, of the same size; E, is a wheel, the size of which is to be regulated by the desired velocity of the drum or axle of whatever kind, round which the ropes carrying the buckets are wound. The axle of the wheel, E, is to be so attached to that of the drum, that it may have a small lateral motion, so as to admit of being thrown alternately into connection with the wheels, C and D, by means of the lever and handle, F. It is evident that E being in connection, or gearing, as it is called, with D, (as represented

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in fig. 2,) will, by a pull of the handle, F, be thrown out of connection with D, and into that with C, and will consequently commence turning in the contrary direction, and so on as often as the handle, F, is moved to the one side or other, while the water-wheel is all the time turning one way. My other plan, fig. 3, is a double water-wheel, A, B, C, D, seen from above for the ease of understanding it; 1, 2, 3, 4, &c. the buckets, divided by E, F, and are on the side; A, D, the reverse of those at B, C; so that water running to the left would fill the buckets on one side, and running to the right the other; suppose the water running in the direction of the arrows, 1, 2, it will fill the part of the wheel towards A, E, turning it in the same direction with the arrows; but if by any means we turn the door, G, H, into the position, G, K, the water will instantly turn in the direction of the arrows, 3, 4, filling the part of the wheel towards C, F, and will turn it in the other direction; and so on alternately as often as the door is turned through the quadrant, H, K; L, M, are the supports of the wheel; O, N, its axle; the end, O, being attached to the axle of the drum, there will be no other machinery whatever required, except it is necessary to increase or diminish the motion of the latter. The change

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