312 TERMINOLOGY. . 



7, Urinoiu for the taste of sal ammoniac ; 



8, Sour for the taste of sulphuric acid, or of carbonic acid. 

 Besides, the intensity or other peculiarities of several 



kinds of taste may be indicated, which is sufficiently plain 

 by the manner in which it is effected in this work. 



Pure artificial salts are most eligible as examples for the 

 different kinds of taste. Some caution is required in ascer- 

 taining this character in unknown minerals. Since in most 

 cases it is quite sufficient to know, whether or not a mine- 

 ral excites some taste, we may also dissolve them in water, 

 because all sapid minerals are soluble in a small quantity 

 of this fluid. 



. 13. ODOUE. 



There are minerals which, either spontaneously 

 or when rubbed, emit some odour, which likewise 

 in particular cases, may afford useful characters. 



Several varieties of black Mineral-resin possess a bitu- 

 minous odour. The species of the genus Iron-pyrites emit 

 a sulphureous odour, when strongly rubbed, as takes place 

 in striking fire. The Arsenical-pyrites under the same cir- 

 cumstances yield an arsenical or garlick smell. Several 

 varieties of rhombohedral Lime-haloide, of prismatic Hal- 

 baryte, of prismatoidal Gypsum-haloide, &c., if rubbed with 

 hard substances, emit an empyreumatic odour ; pebbles of 

 rhombohedral Quartz, and other hard bodies, if rubbed 

 against each other. Several Resins produce a peculiar 

 odour, if rubbed against soft substances. 



Certain species of Gas, of expansible Acids, possess a 

 peculiar kind of odour ; that of rotten eggs, of rotten fish, 

 of burning sulphur, &c. 



Besides the characters treated of till now, there are still 

 some more phenomena which have been employed as such, 

 by mineralogists. Among these, the Adhesion to the tongue 

 is almost exclusively met with in decomposed minerals; 



