PRIZE CHRONOMETERS. I have exhibited in defending my conduct against the unmerited aspersions that have been cast upon it. How far the honest indignation I have expressed will admit of such a charge, I leave your discerning readers to determine; but I can assure this gentleman, that I shall be governed by no man's advice in regulating the language which I may think proper to use against an individual who attempts anonymously to vilify his neighbour. Nor do I envy any man his feelings, who can tamely suffer his character to be traduced, without exposing the author to the contempt he merits. This Correspondent, who calls himself a real workman, but not a rival of mine, thinks I am bound in candour to come forward and avow whether I am, or am not, the real maker of all the chronometers which have appeared at the Royal Observatory in my name, that I may thereby silence the complaints of real workmen." I know of no such complaints. Certain it is, that none of my workmen have complained, and with those of others I have nothing to do. But I must protest against the right of any man to interfere either with myself or my men; nor do I feel myself bound to answer interrogatories which are manifestly impertinent. It is well known that a chronometer is not the production of a single mechanic, but the result of the combined labours of many: I must, therefore, protest, on general grounds, against the right of any individual workman to claim to himself the honours that exclusively belong to his employer; and if workmen cannot complain individually, they cannot collectively. Moreover, as workmen cannot have their names attached to their employers' machines, they can have no responsibility; and, consequently, it is he alone who makes himself responsible, and who must bear the obloquy of bad performance, that is justly entitled to whatever credit may attach to the good performance of his machines. The laws that regulate master and workman are perfectly well understood; it is a voluntary compact, and the moment the workman has completed 253 his contract, and received his wages, true." Your Correspondent wishes farther to insinuate, that I am ignorant of the instrument which the term chronometer is intended to express ; but had he made himself acquainted with the derivation of the word, he would not have risked such an assertion. Chronometer is derived from Xpovos, time, and μerpw, to measure; and, therefore, every machine for the admeasurement of time is, in the most rigid acceptation of the term, a chronometer. But I am as well aware as your Correspondent, or any other man, that the word chronometer is applied by the scientific world to those machines only that measure time most correctly, as box and pocket chronometers, astronomical clocks, &c. Indeed, every machine to which the compensation for heat and cold is PROPERLY applied, whether it be in the balance or the pendulum, may be strictly termed a chronometer; and in the knowledge and experience of this application, as well as every other department of my business, I yield to no man. I would, however, evince little prudence in imparting this knowledge and experience to the public, through any other medium than that of my machines; and I 254 VIATOR'S " PERPETUAL PUMP." rejoice to say, that the character which they have obtained for me, has placed me beyond the reach of any influence which jealousy or envy may endeavour to excite against me, and for which I can never feel too grateful to an enlightened and discerning public. J. M. FRENCH. Royal Exchange, July 14th. [We are sorry that the above letter reached us a few hours too late to have a place in our last Number. To communications which involve the vindication of character, or correction of error, we make it an invariable rule to give immediate insertion.-EDIT.] VIATOR'S" PERPETUAL PUMP." SIR, As the motto of your 93rd Number, and immediately over its frontispiece," the Perpetual Pump" of Viator, stands the_truly philosophical sentiment-" It is always requisite to think justly, even in matters of small importance." Subscribing most fully to the Fontenellean maxim, and perceiving your Correspondent, "Viator," to be in error in this "matter of small importance," I take the liberty of addressing to you a letter, for the purpose of pointing it out. By the design (and explanation), it is proposed that a sort of box shall be divided into two parts, and placed about the centre upon an axis; one part to be filled with stones, and into the other to run a stream of water (the other end of the box, with the stones in, to be attached to a pump-handle). When the said compartment has a quantity of water in it, greater than the weight of the stones in the other, that half of the box will begin to descend (and, of course, the other to rise), but it will not, as supposed by Viator, empty itself; but, on the contrary, only such a quantity of water will flow out of it, as that which remains will have just sufficient power to keep the box in that inclined position, in which exactly as much water will run out as runs in, and then the perpetual pump" must, of neces sity, stop; because the two weights will have found the point of equilibrium, from which there is nothing to disturb them. It is true, Sir, that a similar machine, with a valve in the bottom or side, might be made to act (with a supply of water) perpetually; but this Viator does not appear to have thought of. Should you deem this worth inserting in your valuable Magazine, I will describe the nature of the necessary valve, &c. in another comMONTIS, Jun. munication. Water is made to fall, as at C, in the figure, into the vessel, D, which is constructed to turn, or swing on an axis, M, and is divided in the middle into two equal parts by a partition. When the base of this vessel is in an horizontal position, the water falls so as to divide itself equally by the partition beforementioned; and in any inclined position the whole quantity of falling water will be received by that side of the vessel which is elevated. In the position shown by the figure, this entire quantity is received by the side, B, of the vessel; when that side of the vessel becomes full, it turns on its axis in the direction of that side, and descends till it reaches and rests on the stop or support, F, pouring out, by this change of position, the quantity of water which produced the motion. The opposite side fills in its turn, and brings the vessel into its first position, resting on the support, G; and the operation is repeated. ( -255 ) NEW IMPERIAL MEASURE. 1⁄2 Pint. Pint Quart 2 Quarts. Gallon. Scale one-quarter of full dimension. SIR, Mr. W. Lake, in your 95th Number, page 175, has noticed some errors in my answer to T. II.'s problem, in No. 80, page 382. I am ready to admit that the figures in the fifth column are erroneous, from an inadvertence in subtraction, and were discovered to be so soon after the paper was sent, which not being inserted for several weeks, I considered it as being laid aside. The whole of the fifth column being unnecessary, should be erased, because the thickness of the metal of the sides both at top and bottom will be the same, and not different, as given by W. Lake. There are several errors in his answer, viz.— 0.4048...... ....0001 6th, of the Half-pint........0.4049..... Thus, with the exception of the supernumerary column, the errors happen to be all on the side of W. Lake, which he will be able readily to convince himself of, by calculating the cubic contents of any of the above measures by the usual 256 NEW IMPERIAL MEASURE, The figure in the preceding page represents the sections of the respective measures, from which it is evident the thickness of the sides, in a direction perpendicular to the axis, both at top and bottom, are alike. The following is a simple method of calculating the dimensions The calculation by logarithms will be thus: Logarithm of 1.744163 0.2415872 P.S. The errors above exhibited are small, and would not have been noticed if W. L. had not considered the former answer altogether erroneous. Some of your Correspondents, perhaps, may give a short and ready method of ascertaining the thickness of a metallic plate, by having its area, weight, and specific gravity. B. C. CORRESPONDENCE. Communications have been received from Mr. Matthews-Amicus Veritatis→→ R. M. T. Harris-Clio-A Subscriber and Journeyman Carpenter S. M. A. R. -J. B. C. D.-J. J. M.-Titus-John M.-F. P.-T. H.-A Blacksmith-X. Y. Z. A Joiner-Stultus-John Williamson. Advertisements for the Covers of our Monthly Parts must be sent in to our Publishers before the 20th of each Month. Communications (post paid) to be addressed to the Editor, at the Publishers', KNIGHT and LACEY, 55, Paternoster-row, Loudon. Printed by MILLS, JOWETT, and MILLS (late BENSLEY), Bolt-court, Fleet-street. |