AMMONIAC. 23 



ALYSSUM (Cruciferce). Lat. for Madwort. Herba- 

 ceous plants, both annual and perennial, chiefly natives of 

 Europe. Some varieties are grown on rock- work. The 

 Sweet Alyssum should be grown where bees are kept. 



AMMONIA, OR VOLATILE ALKALI. This gaseous 

 substance consists of hydrogen and azote only. It acquired 

 its name from its being prepared in the East, from camels' 

 excrement, nigh a temple consecrated to Jupiter Ammon. 



This alkali is very extensively diffused, and to its presence 

 in liquid manures and organic substances is mainly owing 

 their efficacy as manures. 



In places overcharged with animal life, this gas exists to 

 an extent injurious to human life. 



AMMONIAC, n. A gum-resin ; the name of two drugs, 

 gum ammoniac, a concrete juice brought from the East, and 

 sal ammoniac, a compound of muriatic acid and ammonia, 

 popularly called hartshorn. ( Worcester.) 



Sal ammoniac is obtained by destructive distillation of 

 bones ; a process by which, on the application of heat, the 

 substance of the bone is dissolved into its simple elements, 

 from which new compounds are formed. Some of these 

 escape in the form of vapor or gas, while the fixed prin- 

 ciples remain in the retort. 



The article used in smelling-bottles, and called salt of 

 hartshorn, and volatile salts, is a carbonate of ammonia ; it is 

 obtained from the horn of the hart, or from any kind of bone. 

 Spirit of hartshorn, called by the apothecaries liquid ammo- 

 nia, is frequently used to cleanse jewelry, applying it with a 

 soft, clean rag, and clearing and polishing it with other dry 

 rags and bits of silk. Stains are often removed by it from 

 silks, gloves, carpets, and worsted materials. As it is very 

 volatile, but a little should be exposed at one time to 

 the air. 



