1835.] Improvements in Science. 207 



mercury and sulphur. It is destitute of taste and smell, 

 insoluble in alkalies, soluble in acids, from solutions in 

 which it is precipitated by water. With sulphuric acid it 

 forms a peculiar acid, which forms a soluble salt with ba- 

 rytes. It suffers no alteration when distilled with nitrate 

 or chlorate of potash. It detonates with saltpetre at a red 

 heat, and also with chlorate of potash at a very high tem- 

 perature. At the ordinary temperatures chlorine and bro- 

 mine have no action on it, but at the boiling temperature 

 chloride of benzine is formed, and in this way the quantity 

 of oxygen contained in it was determined. It is composed 

 of Carbon . . . 66.42 



Hydrogen . . 4*52 

 Sulphur . . . 14-57 

 Oxygen . . . 14*49 



100-00* 

 Madder is such an important article in the art of dye- 

 ing, that its proper culture and natural history have justly 

 attracted the attention of chemists. Schlumberger, a Ger- 

 man, has lately published an account of a series of experi- 

 ments, which he has made for the purpose of determining 

 the causes of the difference between the madder of Alsace, 

 and that raised in Avignon, from which he has inferred, 

 that carbonate of lime is indispensable, that, when we 

 wish to dye red and violet colours with madder upon 

 cotton with an alum or iron mordant, if we use Avignon 

 madder the addition of lime is in general unnecessary, be- 

 cause it naturally contains carbonate of lime, except in a 

 few instances where the plant has been raised on a soil 

 containing little calcareous matter; while the Alsace mad- 

 der which contains only a small portion of lime, although 

 it can produce as deep a shade as the former, yet does not 

 form so permanent a colour ; but when lime has been added, 

 the dye is equal to that of Avignon. Besides lime, there 

 are several other substances which produce standing colours 

 with madder These are in the order of their power, car- 

 bonate of lime being the best, phosphate of lime, carbonate 

 of magnesia, hydrous protoxide of lead, protoxide of zinc, 

 carbonate of zinc, protoxide of manganese, hydrous per- 



* Ann. de China, lrii. 85. 



