1835.] on Malt, 449 



The process of malting consists essentially, 1st,, in pro- 

 ducing a change in the constituents of grain by inducing 

 germination ; and 2nd. in stopping the vegetation when it 

 has been carried to a certain extent, by exposure to heat. 

 ( To be continued.) 



Article VII. 



Analysis of Wolfram. By Mr. Thomas Richardson. 



V< 



In 1781 Scheele discovered a peculiar substance in a heavy 

 white mineral found in Sweden, to which he gave the name 

 of Tungstic acid, the base being called Tungsten from its 

 weight. Shortly after this Messrs. D'Elhuyart obtained 

 the same acid in a mineral called by the Germans wolfram, 

 which had been analyzed in 1761 by Lehmann, who con- 

 sidered it to be a compound of iron and tin. Weigleb and 

 Klaproth also analyzed this mineral, but nothing can with 

 any confidence be drawn from their results, both of them 

 having a deficiency of upwards of 21 per cent. Vauquelin 

 repeated the experiments of the Elhuyarts in 1706*, and 

 obtained the following : 



Tungstic acid ...... 67*00 



Protoxide of manganese . . 6 25 

 Protoxide of iron .... 18*00 



Silica . ... . . . . . 1-50 



92-75 

 Part of the iron Vauquelin supposes to be in the state of 

 peroxide. But even if this supposition were adopted there 

 would still be too great a deficiency to warrant us in 

 drawing any conclusion from the analysis. Berzelius 

 published a set of experiments upon tungsten in 1815, and 

 states the composition of this mineral to be, according to 

 his analysis : 



Tungstic acid ..... 74*666 

 Protoxide of manganese . . 5*640 

 Protoxide of iron .... 17*954 

 Silica 2*100 



100000 



VOL. I. -i G 



