136 Proceedings of the Eoyal Society of Edinburgh. [Sess. 
Pure hydrogen was made by the action of sodium hydroxide solution 
on aluminium foil, and was purified by passing over sulphuric acid and then 
over pieces of bright sodium. Ammonia was made by dropping the concen- 
trated aqueous solution on to sticks of sodium hydroxide, and was purified 
by passing over solid potassium hydroxide and then over clean sodium. 
In making an experiment the tube was filled with hydrogen and 
weighed. A piece of clean sodium, purified by melting under paraffin wax, 
and kept under light petroleum, was then quickly put into the boat, which 
was at once replaced in the tube. A current of hydrogen was then passed 
through, with gentle heating, to remove the petroleum. The tube was 
again weighed. The weight of sodium having been obtained, ammonia 
was allowed to ffow through, the tube being heated to 200°. The issuing 
hydrogen was collected in a Schiff nitrometer fflled with 20 per cent, 
hydrochloric acid. When hydrogen no longer came off, the tube was 
cooled, the ammonia was displaced by hydrogen, and the tube was weighed. 
The change in weight showed the conversion of the sodium to sodamide 
to be complete. 
The reaction tube was then heated and the pure hydrogen passed 
through it. A deposit of the finely crystalline hydride slowly appeared 
on the inside of the cool ends of the tube. After about one and a half 
hours the evolution of ammonia became very slow. At this stage, though 
it was evident that the reaction had affected only 25 per cent, or less of the 
sodamide, the tube was cooled, fflled with hydrogen, and weighed. 
In order to measure the hydrogen evolved by the action of water, the 
tube was evacuated by a Topler pump and connected by one of its leading 
tubes to a Hempel burette filled with dilute sulphuric acid. By dipping 
the other leading tube into a beaker of dilute acid and opening the stop- 
cock, acid was also drawn up into the reaction tube. The ammonia evolved 
was absorbed by the acid, and the hydrogen was drawn over into the 
burette and measured. 
The results are given below : — 
Tempera- 
ture. 
Weight of 
Sodium. 
Soda- 
mide 
formed. 
Sodamide 
calculated. 
Loss of 
weight in 
Hydrogen. 
Hydrogen 
evolved on 
action of 
water. 
Hydrogen 
calculated 
from loss 
of weight. 
Ammonia 
evolved 
on passing 
Hydrogen. 
240°-250° 
• 341 gm. 
(from stock) 
41 c.c. 
44 c.c. 
245°-250° 
•2676 gm. 
•4520 „ 
•4541 
•0251 
34-8 
37-5 
250”-260° 
•3010 „ 
•5085 „ 
•5108 
•0376 
57-2 
56-1 
245“-250° 
•2551 „ 
•4344 „ 
•4330 
•0300 
44-0 
44-8 
