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more rapid. It cuts a perfectly smooth hole, and clears itself as it advances.

The utility of an auger possessing such superior advantages to shipwrights, as well as a variety of other artizans, must be immediately obvious; and one circumstance which renders it still more valuable is, that its form is such that it can be sharpened from time to time upon an ordinary grindstone, without in the slightest degree altering

its figure; indeed it will retain the same form and properties even though ground down to within a short distance of the stem.

Not having the inventor's permission, we refrain from publishing a particular description of this instrument; but as soon as the specification is enrolled, which will be in May, we propose to ourselves the pleasure of presenting it to our readers in a more perfect state.— London Jour. of Science and Arts.

ON THE CAUSE OF HEAT PRODUCED BY FRICTION.

To the Editor of the

American Journal of Science and Arts.

DEAR SIR,-I have made some attempts to explain the cause of the heat excited by friction, an account of which I hope will be acceptable to you.

In rubbing two bodies together, it is evident that the air in their pores and interstices will be compressed, and as air readily yields heat by pressure, it is possible that the heat excited by friction may be thus explained.

If two substances were rubbed together, and if, at the same time, there could be similar friction in vacuo, by a comparison of the results an opinion might be formed of the effect of air with friction in exciting heat. I mentioned this explanation to Professor Renwick, and Dr. M‘Neven; they thought it probable, furnished air-pumps, and assisted in making experiments.

A wooden spindle was fitted to a socket, and a similar spindle also fitted to a socket within the receiver of an air-pump, these were connected by a brass rod, passing through a collar of leather, and being quickly turned by a cord, heat was readily excited;

several trials were made, in all of which, except one, when the density of the air was diminished, less heat was excited. In that, about fourteen-fifteenths of the air was exhausted-notwithstanding this, the heat was greater within the receiver than without. In this instance, pressure was applied as far as could be, and allow the spindle to turn rapidly, the experiment was afterwards repeated with the same apparatus and gentle pressure, and the heat was much greater without the receiver than within.

Upon considering all the experiments, there appears reason to believe that air assists in exciting heat by friction, and the question arises, is it wholly by compression, or is there any other cause?

If the experiment should be repeated it would be well to ascertain that the spindles excited equal heat-that time be allowed for the air to leave the pores of the woodand that the density of the air in the receiver during the experiment be noted. Respectfully, yours,

JAMES T. WATSON.

New-York, 8th May, 1824.

PROFESSOR ANDERSON & DR. BIRKBECK.

[HAVING already devoted so much of our pages to the discussion of this question, we are unwilling that it should not be satisfactorily settled, previous to our giving it up. We have, therefore, inserted Mr. Barclay's letter and those extracts from what appeared in the Free

Press, which we conceive of importance to the subject. Mr. Barclay says in his letter, that Mr. Hart has not met him on the merits of the question. But we conceive Mr. H. did not mean to do so, but having been referred to by Mr. B. in a previous letter, came forward merely for the

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To the Editor of the GLASGOW MECHANICS' MAGAZINE. GENTLEMEN,-I observe in last Saturday's Magazine, a letter from Mr. Robert Hart, on the subject of Dr. Birkbeck's claim to the formation of classes for the scientific education of Mechanics. Mr. Hart himself, I am certain, does not imagine that he has at all met me on the merits of the question; yet as a name has been given, your readers will find that in next Saturday's Free Press, I shall have fully redeemed my pledge, to substantiate my position. I have chosen this channel of communication, as my proofs will be bulky, and I conceive, (as yourselves have hinted,) that your columns may be better applied. As the controversy, however, has arisen in your work, leave to yourselves to make use of such of the documents I shall lay before the public, as you may deem to bear the most on the dispute. I hope to be no farther troubled in the matter; but at all events I trust that if any thing farther is to be said, the remarks on both sides may be better tempered with that spirit of charity which science should ever engender. Wishing you every success in your labours, I remain,

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In the year 1800, we called on Dr. George Birkbeck, then Professor in Anderson's Institution, respecting a question we wished explanation upon. After giving his opinion, he mentioned his desire to do something for the instruction of the Mechanics of Glasgow; whom he described as a very useful class of the community. requested us to call back upon him when he should have bills ready for distribution. We called back, and according to his desire, we distributed the bills amongst the workshops, mason sheds, &c. At the beginning of the course, there were a thin attendance, but which increased, towards the conclusion. The course was gratuitous; and at the end

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of it, or of the second course, a silver cup was presented him, being delivered, in presence of the Class, by John Roberton, Engineer. The second course, next winter, was crowded, and a fee of 1s. was charged to pay the operator and charges. Whilst Dr. Birkbeck was absent from Glasgow, the third course was commenced, and a fee of 5s. exacted by the Directors. On the Dr.'s return, he remonstrated at the charge being made, and the charge was reduced to 2s. 6d. We attended the whole three courses, and are perfectly satisfied with the fact, which must be known to all concerned, that Dr. Birkbeck was the first who commenced the Mechanics' Class; and that neither in the College, nor Anderson's Institution, were there any Class where the Operative Mechanic could obtain instruction at a cheap rate, and suitable hours, until Dr. B. commenced his course, as before mentioned, in 1800. In the Session 182223, we came before the Mechanics' Class, and stated the above facts, when a Committee was named, of which we were Members, and Dr. Ure, Convener; when, after examining the Will of Professor Anderson, and the Sederunt Book of the Managers, the Committee (of which Messrs. Hart and Watt were Members,) were unanimously of opinion that Dr. Birkbeck was the founder of the Class, and the Members being of the same opinion, an address was prepared by Dr. Ure, and subscribed by the Class.

ALEXANDER ROBERTSON, Pattern-
Maker, Gorbals.

DANIEL BLACK, Teacher of Mathematics, No. 76, Hutcheson-Street. Glasgow, 31st January, 1825.

We attended Dr. Birkbeck's first two courses to the Mechanics of Glasgow, in 1800 and 1801, since which we have, with little interruption, been Members of that Class; and we do confirm the truth of the statement of Messrs. Robertson and Black.

WILLIAM MURRAY, Manager, Claud
Girdwood & Co.'s.
JOHN SCOTT, Wright and Builder.
2d February, 1825.

No. V.-Address to Dr. George Birkbeck, (drawn by Dr. Ure and the Committee, whereof Mr. Robert Hart was a Member.)

SIR, We, the Members of the Mechanics' Class, Anderson's Institution, Glasgow, impressed with a deep sense of the

benefits resulting from the course of lectures for instructing artizans in the scientific principles of the arts and manufactures, beg leave, in this respectful manner, to tender our grateful recollections to you, by whom that plan was first projected and carried into execution.

It was your distinguished lot, Sir, to lay open more widely than had been previously contemplated, the portals of philosophy, and to invite artizans, of every description, to enter them, however scanty their means, or obscure their condition.

For this truly philanthropic deed, we present you thus publicly with our most heartfelt thanks; and, while from your approving conscience you will derive the purest satisfaction, you will not disdain the homage now offered you, after an interval of nearly 20 years, by the Students of that Class which you first called into being.

With every kind wish for your prosperity and happiness, we subscribe ourselves,

SIR, your most obedient Servants,

(Signed)

FRANCIS JENKINS, President of the Committee of the Mechanics' Class for 1822-23.

WILLIAM MURRAY, Vice ditto.
HUGH BARCLAY, President of the
Mechanics' Class for 1823-24.
NINIAN PURVES, Vice ditto.
And about 400 others.

No. VI.

We have attentively read the article subscribed B., in No. LIV. of the Glasgow Mechanics' Magazine, and having been Office-Bearers of the Mechanics' Class in the year there alluded to, we declare that the facts therein stated are all true, and as Members of the Committee, we do solemnly deny that we ever dictated to, or interfered with, the Committee for managing the memorial to Dr. Birkbeck; and that Committee must be grossly defamed if it is alleged they acted, or were capable of acting, at our instigation. We have been long Members of the Mechanics' Class, (some of us upwards of twelve years,) and from all we know and have heard, are satisfied that the merit of originating the Mechanics' Class belongs to Dr. Birkbeck, and he alone. (Signed)

FRANCIS JENKINS, Preses.
WILLIAM MURRAY, Vice-Preses.
WILLIAM WARREN, Treasurer.
JOHN ROSS, Secretary.

JOHN LIDDELL, Assistant Secy.

To the Editors of the GLASGOW MECHANICS' MAGAZINE. GENTLEMEN,-Averse as I am to controversy, and inconvenient as it must be to a mind occupied, as mine is, by professional duties, your having permitted my name to appear, treated as it is, so unceremoniously in your publication, Nos. LV. and LVII. Vol. II. leaves me no choice. I cannot, therefore, avoid shortly replying to the groundless insinuations of the anonymous Aliquis, and the equally groundless charge of Mr. Robert Hart.

Whatever my duty obliged me to do, whilst acting as Treasurer for the Mechanics' Class, Anderson's Institution, my conduct, I feel assured, will bear the strictest scrutiny; I shall, therefore, not trouble your readers with any defence, farther than the mis-statements of Ali. quis, which carries refutation upon their very face, affords. It was never intended I should conduct a Mechanical Drawing Class in the Mechanics' Institution, not being a Teacher of Mechanical Drawing. I was indeed appointed to deliver a Course of Lectures on the Theory and Practice of Drawing, as connected with the various branches of the Art. Why those Lectures were not delivered, is known to those whom it concerned, amongst which Aliquis cannot rank himself, and is therefore entitled to no farther information on the subject.

The paragraph he preludes with Warren & Co. is a gratuitous effusion, which he endeavours to give authenticity to by adding an interpolation of the 15th Rule, which, being printed with the Catalogue of the Mechanics' Class Library, Anderson's Institution, 1822, your readers can, by comparing, ascertain the credit due to the statement of Aliquis. I have read, several times, what has been printed as a copy of Dr. Anderson's Will: I have it not now by me to compare, but my memory fails me very much, or Aliquis has stated new matter. His asser

tion, however, is of such a questionable nature, that replying farther would be as unnecessary to your readers as it would be useless to him.

I regret much to see Mr. Robert Hart place himself in such a situation; for, if he establishes what he states, and I deny that I dictated to him the portions of the Will which he read to the Class, and that I successfully deterred him, and the respectable Committee with which he

acted, from freely expressing their opin ions and belief, what becomes of his firmness in the discharge of a public duty? If I did not interfere in the matter but in public, like any other individual of the Class, which I affirm and can prove was the case, what claim has his statements upon the attention of your readers? In duty to myself, and with due deference to the opinion of society, I have thus been forced to trespass upon my time, and the attention of your readers.

In concluding, I beg leave to add my belief with respect to who was the founder of the Mechanics' Class, a belief, strengthened by what Mr. Hart and the gentlemen with whom he acted, appointed to investigate the matter, declared, as the result of their research; Dr. Birkbeck established, in 1800, the Mechanics' Class, and Dr. Ure commenced the Mechanics' Library in 1808.

With all due respect to the memory and benevolent intentions of Dr. Anderson, I could not, in reading the Will, or in what I heard on the subject, find even the smallest reason to suppose that Dr. Anderson any more contemplated the establishment of a Mechanics' Class in his Institution, than the New Town Building Company, when they erected

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USEFUL RECEIPTS.

1. To make Sugar-of-Lead. Boil ceruse, with distilled vinegar, in a leaden vessel, until the vinegar becomes sufficiently sweet-then filter the vinegar through paper, and after due evaporation set it to crystalize.

D. M. B.

2. Method of preserving Oranges and Lemons.

Take small sand, and put it into an oven to dry; after it is cold, put a quantity of it into a clean vessel, on which set a laying of oranges or lemons, the stalk-end downwards, so that they do not touch each other, and strew in some more of the sand, as much as will cover two inches deep, and so on till filled; then set the vessel in a cold place. By this means they may be had in perfection at any season of the year.—J. T.

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SELF-ACTING PUMP. GENTLEMEN,-In the Mechanics' Magazine, No. LVI. Vol. II. (for Saturday, 22d January, 1825,) there is a sketch of a Self-acting Pump (Fig. 2,) on the Plate. I have occasion to irrigate a piece of meadow, through which a burn runs in a channel about five feet deep, which, from the levelness of the adjacent grounds, cannot be damed up more than to give it a fall of two and one half feet, and the water that could be got raised would require to be lifted at least ten feet from the bottom of the burn.

Query.-Could the above pump be applied to such a situation? and, if it could, what size would it require each particular part of the pump to be to accomplish this? and what quantity of water would be necessary to run into the cistern A?

If the above pump is not suited for such an operation, could any of your Correspondents inform me of a plan suitable to such a purpose?

If the Self-acting Pump would work in such a situation, the upright bore H would require to be eight inches dia

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Queries for Builders Answered. GENTLEMEN,-In No. LVI. Vol. II. page 431, you have some queries to Builders. My opinion is, that an 18 inch wall of brick is equal to one of stone of 24 inches, either built as ruble or ashler; and in the same proportion with all the other thicknesses. Parapet, if well built, I think is as good as brick with the same thicknesses, or even better than brick.

You wish also to know whether the ends of joists ought to be fast or not? If the floor is not to be much shaken, such as by dancing, they will be better fast; if to be shaken, it will be better for the walls that they be loose at the ends; but the walls will need to be studied by some other means-say a joist kept out of the reach of the flooring deals, and placed at every third joist, the ends of it made completely fast in the walls. A MECHANIC.

Glasgow, 8th Feb. 1825.

NOTICES TO CORRESPONDENTS.

We have received communications from G. M., Mechanicus, R. F., &c.-We refer P. T. to page 480 of Vol. I. of that excellent and useful work of Dr. Crell's, "The Family Oracle of Health." We are not thoroughly versant in the matters referred to by J. P., but doubt not he will find a good answer to his question by referring as we recommend.

Communications from intelligent Mechanics will be very acceptable, in whatever style they may be written, if they contain a full account of the invention or improvement, which is the subject of their notice.

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

CURLL, PRINTER.

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