MR. WATSON SMITH ON ISODINAPHTHYL. 



19 



a somewhat larger yield was obtained in the second and 

 subsequent distillations than in the first. These distillations 

 were repeated seven times, to accumulate crude material. 

 The temperatures at which the tube was maintained were 

 not uniform in each experiment ; and the volume of gas 

 evolved was found to vary accordingly. Thus in the second 

 distillation, the heat was only just perceptibly red, and 

 very little gas was obtained (about 5 cub. cent, or so). 



Quantities of Gas liberated during each experiment, the 

 heat employed varying in intensity. 



Distillation. 



Intensity of heat 



Cub. cent, of gas 





of tube. 



evolved. 



1 st. 



Bright red heat. 



300 



2nd. 



Only just red. 



Very little, about 5 cb.c. 



3rd. 



Bright red. 



460 



4th. 



Do. 



300 



5th. 



Do. 



500 



6th. 



Do. 



403 



7th. 



Do. 



300 



8th. 



Do. 



• 



225 

 Total 2493 



Average temperature=i5° C. 



The above measurements of gas evolved were not made 

 with any great accuracy, but are just fair approximations. 

 This gas was tested, and yielded the following results : — 



1st. It gave no milkiness with lime-water. 



2ndly. It burnt, on ignition, with a lambent bluish 

 flame, tinged at times with a glimmering of the white 

 carbon-flame, and on shaking with lime-water gave there- 

 with a very slight milkiness ; but almost always there was 

 not the slightest glimmer of the carbon-flame, and not the 

 slightest cloud with lime-water after burning. 



3rdly. The gas, mixed with \ its volume of oxygen and 

 inflamed, exploded loudly. 



"Prom these evidences we gather that the gas is hydrogen ; 

 and the glimmering at times of the carbon-flame was pro- 



c2 



