1819.1 Prof. Fuchs on Lasionite and Wavellite. 279 



of silica in potash, which I had found to answer very well in 

 former experiments. Twenty-five grains of wavellite were dis- 

 solved in potash ley, and this solution was mixed with liquid 

 silicate of potash, which contained an equal quantity of silica. 

 There was immediately formed a thick slimy matter, from which 

 by dilution with water, and boiling, a copious precipitate fell, to 

 which I shall give the name of A. The liquid filtered from this 

 precipitate was mixed with sal-ammoniac, without becoming 

 niudclv. It was then evaporated to dryness. The residual 

 saline mass dissolved completely in water, and was neutral. It 

 was mixed in the first place with some ammonia, aud then with 

 muriate of lime, which occasioned a copious precipitate, lhis 

 precipitate was separated immediately by the filter, washed with 

 hot water, dried, and heated to redness It weighed 19-4 gr 

 and exhibited the properties of neutral phosphate ot lime. It 

 dissolved readily and completely in nitric acid ; and during the 

 solution some small air-bubbles were extricated. It was thea 

 thrown down from the acid in the state of phosphate oi lead. 



The precipitate A, which contained the alumina united to 

 silica * was carefully collected, and treated with muriatic acid. 

 It dissolved rapidly and completely, and the solution assumed the 

 form of a stiff' jelly. From this the silica was separated m the 

 usual way. The alumina was then thrown down from the solu- 

 tion by ammonia. It weighed 9*3 gr. 



As 19-4 ^r. of phosphate of lime contain 8-78 gr. of phosphoric 

 acid, we have the constituents of wavellite as follows : 



Alumina 9-30 



Phosphoric acid 8-78 



Water 7 ' 00 



25-08 



Consequently 100 parts contain, 



Alumina ^*7o 



Phosphoric acid 35*1- 



Water 28'OQ 



100-32 

 The small excess may proceed from a little carbonate of lime 



Wear h from Marmaroscb, obtained a precipitate of ^P h ° s P''" Sis *"£ 

 Solved in potash. (See Bei.rage, iv. 366.) It ■■ to be presumed that tins preci- 



PU ri Sfil tSSXk wheTa'olution of silica and of alumina in an alkali 

 » J J£5 olelher the two earths do not precipitate alone, as has hitherto been 

 ZSftSSS SSS considerable quLtiJ of the alkali Hence te reason 

 whv the precipitate dissolves completely in acids and forms a jelly with i"eu»,as >"» 

 The case w ith na trolite and fatstone. I f soda be employed in this experiment .we 



the Transactions of the Academy of Sciences in Munich. 



