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APPENDIX. 



act upon sugar, the sweetest of all things, produces a sub- 

 stance intensely bitter to the taste. Charcoal is, of all 

 known substances, the most difficult to convert into vapor ; 

 so much so, indeed, that the conversion has never yet 

 been decidedly effected ; it is also a very solid substance ; 

 and diamond, which is nothing but crystallized charcoal, is 

 one of the hardest bodies in Nature. Sulphur, in the solid 

 state, is also a hard substance, and to hold it in vapor re- 

 quires a high temperature. But when these two substan- 

 ces, carbon and sulphur, are made to combine chemically 

 so as to form the substance called bisulphuret of carbon, 

 their properties are strikmgly changed. Instead of the 

 compound being hard, it is a thin liquid, and is not known 

 to freeze or solidify at any degree of cold that can be 

 produced. Instead of the compound being difficult to va- 

 porize, it is, of all liquids, one of the most evaporable. 

 Charcoal is the blackest substance with which we are ac- 

 quainted — sulphur is of a most lively yellow hue ; but the 

 compound is as colorless as water. A new smell and taste 

 are acquired, and, in a word, there is not one point of re- 

 semblance with the constituents. These facts are strikingly 

 illustrative of the change of properties which follows on the 

 exertion of chemical attraction between the ultimate parti- 

 cles of bodies. — Donovan^s Chemistry. 



