1 50 Intelligence and Miscellaneous Articles, 



its weight is diminished 19 to 21 percent. After calcination it is 

 sensibly magnetic. 



Muriatic acid acts very readily upon it j the solution does not con- 

 tain the smallest trace either of manganese, protoxide of iron, or of 

 alkali : it contains peroxide of iron, alumina, and magnesia j the in- 

 soluble portion is gelatinous, and is composed of silica, soluble in the 

 alkaline solutions, and sometimes mixed with a small quantity of 

 clay, when the mineral has not been picked with sufficient care. 

 By analysis this substance yielded 



Silica 44- 



Peroxide of Iron 29* 



Alumina 3*6 



Magnesia 2*1 



Water 187 



Clay 1-2 



986 Ibid, p. 22. 



ANALYSIS OF SOME VEGETABLE PRODUCTS. 



M. F. Marcet has analysed some vegetable bodies : the method 

 employed was that proposed by M. Gay-Lussac of using peroxide of 

 copper. Common starch yielded 



Carbon 437 



Oxygen 497 



Hydrogen 6 6 



100- 

 Roasted starch gave 



Carbon 357 



Oxygen 58*1 



Hydrogen 6'2 



100- 

 It appears therefore that roasted starch contains much more oxygen 

 and less carbon than common starch. Hordein is the name given by 

 Proust to a substance separated from barley flour. It yielded 



Carbon 44'2 



Oxygen 47*6 



Hydrogen 6*4 



Azote 1 *8 



100- 

 M. Marcet remarks that some chemists have considered this sub- 

 stance as a modification of starch, and others as analogous to saw- 

 dust. Dr. Thomson appears to regard it as of the same nature as the 

 parenchyma of the potato : this latter substance gave M. Marcet 



Carbon 37'4 



Oxygen 58'6 



Hydrogen 4* 



100- It 



