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. 1865 Excerpt: ...J "Meteorology," from the' Encyclopa-dia Britanniea, ' by Sir J. Herschel, p. 50. but only the transport of moisture, and in some measure also of heat, whilst in the second case the vapour elevates the atmosphere, moves masses of air from their place, and thereby every change in the vapour produces a corresponding change in the equilibrium of the atmosphere. I will now discuss more accurately some points in the vapourtheory itself. In the first place it should be remarked that Dalton, when led by his experiments to consider every gas as independent by itself, and not subjected to the pressure of the rest, first conceived this effect to exist in the mixture of permanent gases, and afterwards transferred this effect to aqueous vapour also. But now, Dalton's previous assumption having been proved to be unfounded in the case of aqueous vapour, it may be asked whether it can be considered as well founded in that of the permanent gases. There would be no difficulty in deciding this by an experiment. I have not, however, performed the experiment itself, because the Amongst the different contrivances which could be formed to make the experiment, the following appears to me to offer the least difficulty in its execution: Take a glass vessel, of the form represented in the figure, consisting of two spheres, A and B, and the open narrow tubes, ab, cd, ef, which proceed from them. At first let the communication between A and B be stopped by the cock g, and fill the half ag with oxygen gas, the half gf with hydrogen, enclosing them by the drops of quicksilver, p and q, upon which the atmosphere presses from without. Now after, under such conditions, equilibrium has established itself, open suddenly the cock g, and the oxygen of the space A will effuse itself, a...