Reply to a criticism of Prof. Olmsted, upon the arguments respecting the materiality of heat / adduced by Dr. Hare.

  • Hare, Robert, 1781-1858.
Date:
[1827?]
Catalogue details

Licence: Public Domain Mark

Credit: Reply to a criticism of Prof. Olmsted, upon the arguments respecting the materiality of heat / adduced by Dr. Hare. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    1/4
    /#n..- REPLY TO A CRITICISM OF PROF. OLMSTED, UPON THE ARGUMENTS RESPECTING THE MATERIALITY QB HEAT, V ADDUCED BY DR. HARE. Y° ' In the number of the American Journal of Science, for October last, I observe some strictures by Prof. Olmsted, on an essay of mine, on the question whether heat can be motion, published in 1822, in Vol. 4 of the same work. The following passage is partially quoted, from Sir Hum- phrey Davy's Elements, by the learned professor, as introduc- tory to his strictures.—I beg leave to quote it in full. It seems possible, says Sir Humphrey Davy, to account for all the phenomena of heat, if it be supposed that in solids the particles are in a constant state of vibratory motion, the par- ticles of the hottest bodies moving with the greatest velocity, and through the greatest space—that in fluids, and elastic fluids, besides the vibratory motion, which must be conceived greatest in the last, the particles have a motion round their own axes, with different velocities, the particles of elastic fluids moving with the greatest quickness—and that in ethe- real substances, the particles move round their own axes and separate from each other, penetrating in right lines through space. Temperature may be conceived to depend upon the velocity of the vibrations; increase of capacity on the mo- tion, being performed in greater space ; and the diminution of temperature, during the conversion of solids or fluids into gases, may be explained on the idea of the loss of vibratory motion, in consequence of the revolution of particles round their axes at the moment when the body becomes liquid or aeriform—or from the loss of rapidity of vibration, in conse- quence of the motion of the particles through greater space. After his partial quotation of this passage, Prof. Olmsted proceeds as follows : He (Dr. Hare) has attempted to show, that the supposition that temperature results from the velocity of the particles of heat- ed bodies subjected to a vibratory motion, is inconsistent with *he laws of mechanics. «It is fully established in mechanics, (says Dr. Hare,) that when a body in motion is blended with, and thus made to communicate motion to another body, previously at rest, or movin-' slower, the velocity of the compound mass, after the impact, will be found by multiplying the weight of each b.-dy by its respective velocity, and dividing the sum of the products by