ALKALIES, 237 



equal in weight to the salt employed ; it is kept cold by ice or snow, 

 or at least by cold water often renewed. When the gas ceases, the 

 addition of a little water to the materials in the retort, will renew the 

 flow of gas, and produce complete decomposition ; ten pounds of sal 

 ammoniac should produce thirty pounds of aqua ammonia?, sp. gr. 

 .950, and containing about 12 per cent, of ammonia.* The Edin- 

 burgh college prepare it of the strength, .989 ; that of London, .960. 

 Ure. 



12. NATURAL SOURCES. 



From the decomposition of animal substances, as in privies and 

 stables,f &tc. ; it is probable that ammonia is produced generally 

 during the spontaneous decomposition of animal bodies ; a pungent, 

 reviving, and antiseptic gas thus springs up, from the very bosom of 

 putrefaction. 



The Chenopodium vulvaria emits this gas in the act of vegetation, 

 and many flowers, even those with an agreeable odor| do the same. 



13. GENERAL INFERENCE. 



In destructive distillation, and in spontaneous decomposition, the 

 appearance of ammonia indicates nitrogen, and of course hydrogen. 



This remark will apply not only to animal substances, but to plants, 

 when they afford ammonia, as all those do which putrefy with an an- 

 imal odor. 



14. POLARITY. 



Ammonia is attracted to the negative pole in the galvanic circuit, 

 and is therefore electro-positive. 



15. COMBINING WEIGHT 17 made up of 1 proportion of nitro- 

 gen 14, and 3 of hydrogen =17. 



16. MEDICAL AND OTHER USES. These are important; taken in- 

 ternally, in the proportion of 8 or 10 drops to a wine glass full of wa- 

 ter, ammonia is a powerful and valuable stimulant, producing the most 

 useful effect of alcohol, but without its mischiefs. It is also an ant- 

 acid. 



Externally, it is a rubefacient, but it is generally used in the form 

 of volatile liniment, made by agitating aqua ammonias in a vial with 

 olive oil. Ammonia is a very valuable antidote to poison. Either 

 the aqua ammoniae, the carbonate, or the volatile liniment may be 

 used externally, and the two former internally.^ 



* The iron bottles in which quicksilver is brought, answer very well for the de- 

 composition of sal ammoniac, and the muriate of lime is easily extracted from them 

 by hot water. 



t In these places, the ammonia is mixed with fetid gases; the pungency belongs 

 to the former, and the disagreeable odor to the latter. The ammonia is often so 

 abundant as to produce a white cloud, when, in these places, the stopper is withdrawn 

 from a vial of muriatic acid. In Europe, ancient hotels are sometimes tilled with 

 ammoriiacal exhalations, arising from the privies within the premises. 



t Jour, de Phar. Feb. 1824, p. 100 ; also, Am. Jour. Vol. X, p. 190. 



$ See Am. Jour. Vol. XVI, p. 183. 



