A Compendium of the Course of Chemical Instruction in the Medical Department of the University of Pennsylvania

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J.G. Auner, 1828 - 356 ページ
 

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309 ページ - Temperature may be conceived to depend upon the velocities of the vibrations ; increase of capacity, on the motion being performed in greater space ; and the diminution of temperature, during the conversion of solids into fluids or 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 consequence of the motion of the...
14 ページ - ... of pressure consequent to its altitude, as denser by the cold, consequent to its remoteness from the earth, and another may be as much denser by the increased pressure arising from its proximity to the earth, as rarer by being warmer. Hence when unequally heated, different strata of the atmosphere do not always disturb each other.
56 ページ - I was subsequently enabled to employ this process, in dividing large vessels, of four or five inches in diameter, and likewise to render it in every case more easy, and certain, by means of a piece of plank forked like a...
9 ページ - I do firmly believe in the existence of material fluids, severally producing the phenomena of heat, light and electricity. Substances, endowed with attraction, make themselves known to us, by that species of this power, which we call gravitation, by which they are drawn towards the earth, and are therefore heavy and ponderable ; by their resistance to our bodies, producing the sensation of feeling or touch ; and by the vibrations or movements in other matter, affecting; the ear with sounds, and the...
15 ページ - ... and nine thousand feet Consistently with the chemical laws, which have been experimentally ascertained to operate throughout nature, air which has been in contact with water, can neither be cooled nor rarefied without being rendered cloudy by the precipitation of aqueous particles. It follows -then, that the air displaced suddenly from the surface of the Gulf of Mexico, by the influx of cold air from the northeast, never rises higher than the elevation mentioned by Humboldt as infested by clouds....
310 ページ - Very delicate experiments have been made to show that bodies when heated do not increase in weight This, as far as it goes, is an evidence against a specific subtile elastic fluid producing the calorific expansion ; but it cannot be considered as decisive, on account of the imperfection of our instruments; a cubical inch of inflammable air requires a good balance to ascertain that it has any sensible weight, and a substance bearing the same relation to this, that this bears to platinum, could not,...
87 ページ - Of course, ascertaining the force with which it rises, by using just weight enough to counteract it, and adding this weight, so ascertained, to that of the cork, we have the weight of a bulk of water, equal to the bulk of the cork. By this, dividing the weight of the cork, agreeably to the general rule, the specific gravity of (he cork will be found.
309 ページ - ... 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 velocities of the vibrations; increase of capacity on the motion being performed in greater space ; and the diminution of temperature during the conversion of solids into fluids or 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...
309 ページ - It seems possible 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 particles 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 velocity, the particles of elastic fluids moving with the greatest quickness,...
74 ページ - ... on each side of the groove. This lateral passage communicates with a hole bored vertically into the wood, by a centre-bit ; and a small strip of the leather, being extended so as to cover this hole, is made, with the addition of some disks of metal, to constitute a valve opening upwards. In the bottom of the cask, there is another valve, opening upwards. A piston rod, passing perpendicularly through the pipe, from the handle ( H ,) is fastened near its lower end, to a hemispherical mass of lead...

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