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XXXVI. An Attempt to analyse Silica. By Professor 

 Berzelius*. 



J- HE attempts hitherto made to decompose silica by means 

 of the electric pile having left the problem undetermi.ied, 

 whether it can be reduced to a metalline bodv like other 

 earths, I attempted to gain an analocous result by mixing 

 it with powdered charcoal and filings of irr)ii, and exposing 

 the mixture, in a luted crucible, to a deoree of heat suffi- 

 cient for the fusion of the iron; hoping that the iron might 

 in this case act somewhat similarly to quicksilver with the 

 electric pile. 



a. Three orammes of iron filings iTiixed with if gramme 

 silica, and 0-66 of a gramme powdered charcoal, were put into 

 a sn)all crucible covered and luted in the ordinary way, and 

 exposed to the heat of a blast furnace for one hour. The 

 mass when cold was taken out, the small reguli of iron 

 were extracted by the magnet, and rubbed with the palm of 

 the hand against paper, until, by continued rubbing on new 

 and clean paper, they ceased to soil the paper. They had a 

 silver colour; some of them admitted of being flattened; 

 others were brittle, according as they had taken up more or 

 less carbon. 1 -5 gr. of these polished metallic globules were 

 then put into sulphuric acid diluted with six times as much 

 water. They ren.ained undissolved till heat was applied, 

 when tiiey dissolved slowly. When all action had ceased, 

 the forms of the globules still remained, but chansed in 

 colour. Some were white as snow; others black, and much 

 like plumbago. When these were afterwards burned in an 

 open fire, there remained siliceous earth of the form of the 

 n)etallic globules. Those that had been white were still 

 white, and those that had been black were now pale red. 

 This earth amounted to 3| per cent, of the weight of the 

 ferruginous globules. 



0. Having perceived the probability that these white 

 skeleton globules of silica were derived froiTi the soft reguli, 

 and the black from those most charged with carbon ; I de- 

 termined to try whether a silicated iron, tolerably free from 

 carbon, might not be obtained by using less charcoal. I 

 therefore mixed equal parts of fine powder of flint and 

 iron-filings wit!) -^'-ih of their weight of pulverized char- 

 coal, using a little nmcilage of gum dragon to form a paste, 

 of which little balls were made. These packed up in fine 

 powder of flints were exposed to the blast in the same man- 



• I'roin /Ifliundli'ii^nr i Fysik, Kemi ncli Mi/itrulogi, ulgifue a/ff. iJisinger 

 pch f. btiteiiui. 3 H; Stockholm. 1810. 



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