Thermo-dynamics treated with elementary mathematics; and containing applications to animal and vegetable life, tidal friction and electricity

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...because the system may be so arranged that the parts which gain and lose heat are all at one constant temperature. (1) For by the fundamental axiom on which Carnot's principle is based, a positive quantity of work cannot be obtained from a cycle when all the parts of the system that gain or lose heat are at one constant temperature. (2) Or we may make use of the equation--+--=. 2 +... 0, which is a deduction from the fundamental axiom for any cycle whatever. When, as in our case, there is only one temperature (9) at which heat is absorbed or evolved, the equation becomes--0, where (7 Q is the total quantity of heat absorbed during the cycle. Hence Q cannot be positive. This result is clearly but a slightly different form of the fundamental axiom, and it'is opposed to the supposition that a positive quantity of heat is absorbed during the cycle. Again, if the tube be plunged in a trough of mercury, it may be shown in like manner that the mercury cannot be depressed in the wide part of the tube below the level in the trough. The second application we shall explain was given by Sir W. Thomson in 1870. Let a fine glass tube A, open at both ends, be plunged in a vessel of water. Then the liquid will rise in the tube, and it is evident that when equilibrium is established, no change will be made by merely closing the lower end of the tube. Hence we infer that if a second tube B, equal and similar to A but with its lower end closed, be held parallel to and on the same level as A, equilibrium will not be established, if there is any aqueous vapour in the air, until the water is at the same level in B as in A. Now when given quantities of air and aqueous vapour (or of any two gases) exist together in the same vessel or space, the pressure and density of each is very...