Elements of chemistry : including the applications of the science in the arts . to remain unchanged, and that the alteration takes place onthe hydrogen exclusively, then the time of passage of the hydrogen has increasedfrom 0-2631 to 0-4510, or been nearly doubled. But it is in mixtures where theproportion of hydrogen is large compared with that of the other gas, that the de-parture from the mean velocity is most conspicuous. Thus the addition of half aper cent, of air or oxygen has an effect in retarding the passage of hydrogen at leastthree times greater than what it should produce from its
Elements of chemistry : including the applications of the science in the arts . to remain unchanged, and that the alteration takes place onthe hydrogen exclusively, then the time of passage of the hydrogen has increasedfrom 0-2631 to 0-4510, or been nearly doubled. But it is in mixtures where theproportion of hydrogen is large compared with that of the other gas, that the de-parture from the mean velocity is most conspicuous. Thus the addition of half aper cent, of air or oxygen has an effect in retarding the passage of hydrogen at leastthree times greater than what it should produce from its greater density by calcula-tion. The time of the effusion of hydrogen thus becomes a delicate test of thepurity of that gas. This want of mechanical equivalency in hydrogen mixtures isexceedingly remarkable, being a marked departure from the usual uniformity ofgaseous properties. TRANSPIRATION OP GASES. The arrangement exhibited (fig. 40), was adopted in examining the rates of passageof different gases into a vacuum through a capillary tube. The gas is taken from a Fig. llllSillKIWIIli ??, .?:??? ill /?- -/ r-^n n U counterpoised bell-jar, standing over the water of a pneumatic trough, and passesfirst by a flexible tube to a U-shaped drying tube filled with fragments of chlorideof calcium, in order to be deprived of aqueous vapour before entering the capillary 86 TRANSPIRATION OF GASES. glass tube a. The last is connected by means of a tube of block tin with a receiveron the plate of an air-pump, provided with a gauge barometer 6, as is allowed to enter the exhausted receiver by the capillary tube, and the tuneobserved which the gauge barometer requires to fall a certain number of inches fromthe admission of a constant volume. It is found that for a tube of any given diameter, the times of passage of differentgases approximate the more closely to their respective times of effusion, the morethe tube is shortened and made to approximate to an aperture in a th
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Keywords: ., bookcentury1800, bookdecade1850, bookpublisherphila, bookyear1853
