362 



SCIENTIFIC RECREATIONS. 



Nitrogen combines with hydrogen, forming various compounds. These 

 are the " amines," also ammonia, and ammonium. Ammonia possesses the 

 properties of a base. Its name is derived from Jupiter Ammon, near 

 whose temple it was prepared, from camels' dung. But bodies containing 

 nitrogen give off ammonia in course of distilling, and hartshorn is the 



Fig. 354. Experiment to obtain nitric acid. 



term applied to horn-cuttings, which yield ammonia, which is a colourless 

 gas of strong odour and taste now obtained from gas-works. 



To obtain ammonia heat equal parts of chloride of ammonia (sal 



Fig. 355. Apparatus for obtaining laughing-gas. 



ammoniac) and quick-lime powdered (sec fig. 357)- The gas must be col- 

 lected over mercury, because it is very soluble in water. Ammonia is 

 useful to restore tipsy people and fainting ladies. A solution of ammonia 

 is used for cauteries. Ammoniacal gas is remarkable for its solubility in 

 water. To prepare the solution the gas is forced through a series of 

 flasks. The tubes carrying the gas should be continued to the bottoms 

 of the flasks, else the solution, being lighter than water, the upper portion 

 alone would be saturated. The tubes carrying away the solution are raised 



