Descriplion and Analjjsis of Eilan. 243 



B. 



Before the blowpipe, without addition, it melts into a trans- 

 parent bead, free from bubbles, and but slightly coloured. 

 With borax it becomes a transparent greenish glass. Fnos- 

 phoric salt decomposes it, leaving a skeleton ot silica ; but the 

 bead, when cool, remains transparent: it more ot the pul- 

 • verized stone be added, the bead, partly transparent while in 

 fusion, becomes quite opake when cool. Soda, in small quan- 

 tities, melts with the pulverized stone, but in large quantities 

 it does not possess diis property. 



C. 

 a ) 4.-025 oranimes of the pulverized mineral dried by a 

 spirit-lamp, left, after having been strongly heated, 4.-899 gr. : 

 100 parts, therefore, contain 0-G06 of volatile matter. 



b.) 5 gr. dried bv the spirit-lamp were heated in a pla- 

 tinum ciucible, for 'two hours, with 25 gr. ot carbonate of 

 barvtes. The fused mass was in one piece, ot a grey-yellow 

 colour; it was dissolved in water, decomposed by muriatic 

 acid, and evapomted. The silica after having been heated 

 weighed 2-(35Sgr. or 53-lGOiJf-rcc«;'. -A.^a^ 



°) The solution, freed from barytes by sulphuric ac d, was 

 afterwards evaporated nearly to dryness : some sulpha e ot 

 lime became separated from it, which, alter having been 

 washed on a filter, dried, and heated, weighed 1-495 gr. con- 

 Uiining 0-62087 of lime, or 12-417 pe?- cent. 



./.)°The liquid separated from the sulphate of lime, gave 

 by means of caustic ammonia, a precipitate, which was heated 

 ith excess of caustic potassa, and alumina was obtained fiom 

 the alkaline solution by saturation with muriate acid, and 

 precipitation by carbonate of ammonia : it weighed, when 

 ^Iripd 0-7017. or 14-034 /J£?r c«i/. 



. 'Thebrmvnresidumn which remained after separating 

 the alumina bv caustic potassa weighed 0-3718. By means^ 

 of snicinic acul, and pLipitation ^^^^^^f^"^ 

 cvrbonate of soda, it was decomposed into 0-3569 ot oxitle ot 

 in,„,=?i 38 ;.;<:.«/., and 0-01491 of oxide ot manganese, 



=iri'-"^e'fluid mixed with caustic ammonia that h^ 

 n.4ed die filter, oxalate of ammonia precipitated oxalate ot 

 lime, which gave 0-17557 of carbonate ot lime, containing 

 0-09902 of lime, = 1 -980 yjcr a"/. 



^) The solution, entirel/freed trom Hmo was now evaporated 



and heated. An unmelted mass remau.ed, winch - - ted a 



large proportion of ma-mesia. It was dissolved in ^u tu, ami 



nixed with hydrosulpfiuret of ammonia, the precipitate de. 



crposed by nuuiali; acid ;^ and the acul fluid, ni a bo^n^ 



