PROFESSOR GRAHAM ON THE MOTION OF GASES. 
381 
The time of methylic ether, 0‘4826, is decidedly longer than that of common ether, 
0*4546, as the latter was formerly observed by the same capillary ; and consequently 
an addition of ether vapour shortens the methylic ether time, as appears in the 
second experiment, where the transpiration time of such a mixture falls to 0*4600. 
14. Hydrochloric Ether {Chloride of Ethyl, C 4 Hg Cl). 
The experiments were made with the same short capillary K, 8*75 inches in length, 
and with the other arrangements as for the two preceding ethers. Thermometer 56°, 
barometer from 29*794 to 29*758 inches. 
The time of air was 980 and 981 seconds ; of hydrochloric ether, 548, 544 and 543 
seconds. 
Air=l. 
Oxygen = 1. 
Transpiration time of hydrochloric ether 
0-5543 
0-4988 
It would be unsafe to draw any conclusion from a single experiment upon this 
ether and that experiment made with a capillary of inferior resistance, but it may be 
remarked that the time of this ether approaches to half the time of oxygen, while the 
density of the vapour is little more than double that of this gas ; the theoretical den- 
sity of hydrochloric ether vapour being 32*25 to hydrogen 1 and oxygen 16. 
15. Hydrochloric Methylic Ether {Chloride of Methyl, C 2 H 3 Cl). 
This ether, which like the two last is entirely vaporous at the temperature of the 
experiments, was prepared by distilling together half a pound of wood-spirit, one and 
a half pounds of oil of vitriol and one pound of common salt. The gas was exposed 
to a large quantity of dilute caustic soda in two wash-bottles, and dried afterwards 
by chloride of calcium. The same capillary and arrangements were employed as in 
the immediately preceding experiments. Thermometer 54°, barometer 29*862 to 
29*856 inches. 
The time of air was 973, 973 seconds ; of chloride of methyl, 592, 587 and 582 
seconds; of chloride of methyl again, after changing the solution of caustic soda in 
the wash-bottles, 592 and 592 seconds. Calculating from the last observed time of 
chloride of methyl, we have — 
Air = l. 
Oxygen = 1. 
Transpiration time of chloride of methyl 
0-6084 
0-5475 
It thus appears that the chloride of methyl has a longer time, or is more slowly 
transpired than the corresponding chloride of ethyl ; as the oxide of methyl was also 
found to be less transpirable than the oxide of ethyl. Indeed the difference between 
the two oxides and between the two chlorides appears to be the same, or about 0*045 
MDCccxLix. 3 D 
