SPECIFIC HEATS OF SOME COMPOUND GASES, 585 












TABLE XXX. 
leh 
t 1 1’ b@e E 
P | Pp 1 v5 dp & 1 B 
94 | 20:8 27-67 49-03 2482 1-014 1-129 4450 
99 18-9 27-49 48:86 2-485 1:015 1-124, 4694 
101 19:9 27:49 48-96 2-486 1-015 1:120 4-883 
122 | 203 27-57 49-05 2-492 1-018 1:128 4-578 
141 20-0 27-43 48-97 2-500 1-021 1:128 4640 
142 19-4 27-42 48°92 9-500 1:021 1-129 4597 
| Wire 5 oe ell SDS 4-640 
i 


§ 15. Methyl Acetate (CH,COOCH,). 
Methyl acetate proved to be more troublesome than any of the other substances 
investigated, and it is with some hesitation that I venture to publish the results of 
my experiments on it. Time after time the liquid was shaken with calcium chloride 
and fractionated, but the boiling-point was never as steady as could be wished. One 
of the decomposition products is methyl alcohol, which has nearly the same boiling- 
point as methyl acetate itself, and cannot be removed by fractionation, so that it 
is hardly to be hoped that the final product was quite pure. 
The experiments with the Kunpt apparatus, given below in Table XXXLI., are not 
the only ones that were made. After each purification several experiments were 
made, and it was found that the wave-length of sound in the vapour gradually 
diminished—presumably in consequence of the gradual removal of methyl alcohol. 
The set given below were made on the particular sample that gave the shortest 
wave-length. 
If the vapour-density determinations gave the true density of the material used in 
the velocity of sound experiments, a little impurity would have scarcely any effect 
on y, but the vapour-density observations are specially liable to error. The quantity 
of methyl acetate used in an experiment is small—not more than a quarter of a 
gramme—and a very little moisture on the glass may bring about the decomposition 
of quite an appreciable percentage of the vapour. It is probably for this reason that 
the experimental error of the vapour-density observations is greater than usual, the 
divergence from the mean reaching 1 part in 400. 
The tabulation of the results is the same as before. Table XXXI. and fig. 10 give 
the relative density determinations. Table XXXII. gives the absolute density 
results, and Table XX XIII. gives the values found for y. 
MDCCCXCV.—A. 4 F 
