228 -COLOURED GLASSES OF THE ANCIENTS. 



mafs. It was again difFufed in a large quantity of boiling water, 

 to which a flight portion of muriatic acid had previoufly been 



S»/« fell down, added. Siliceous eartk feparated ; which, colled^ed, edulco- 

 rated and ignited, weighed 14-2 grains. 



The remaining (b) The filtered folution pofTelTed a green colour ; and when 



^°'"5'""'^,'P°'''''^ concentrated by evaporation, it depofited needle-ftiaped cryf- 

 cryftals of mu- ,,, J r ' r r.r 



riatc of lead by tals. When on continuing the evaporation no more luch cryl- 

 evapojation. (als would appear, the remaining fluid was diluted with fpirit 

 of wine, and thrown upon the filter. The colleded cryftals 

 were waflied with fpirit of wine and dried in a warm tempera- 

 ture, upon which they weighed 32^ grains. They confifted 

 of muriated lead, equivalent to 2S grains of gently ignited 

 oxide of lead. 

 The liquid was (c) I then fuperfaturated with caiijUc annnonia the folution 

 iated wfth am".' ^^^^ ^'^^^ ^'""'^ '^^ contents of lead. It was now of a dark-biue 

 monia, and alu- colour, a«d let fall a grey precipitate; which being feparated, 

 *'*^ir^^ ^*P^' the folution was again neutralized with muriatic acid, reduced 

 The rem. fluid by evaporation, and upon this combined with oxalate of potajh 



being fat. with ^^ j^ppr as any turbidnefs enfued. The precipitate thence 

 mur, acid, then „ f ■', ,.,. , . , . ^ ^ . ^. . • , , , 



evap. and precip. lormed was Oxalate nr lime, which alter Itrong ignition yielded 

 by oxalate of three grains of pure calcareous earth, 



of lime. ' ('^■^ The ingredient copper was now precipitated from the 



C9/'^«r was then folution, by immerfing into it a poliflied piece of iron. The 

 prei-jp. y iron. j,ggy]jpg copper obtained by this procefs amounted to twelve 



grains, for which fifteen grains of oxided copper muft be put 



in the account. 



Purification of (e) The above grey precipitate (c) thrown down by the 



the precipitated cauftic ammoniac, was mixed and digefied with liquid caufiic 

 alumine. , . i j 



foda. When to the filtered folution, again fuperfaturated with 



muriatic acid, carbonate of foda was added, aluminous earth 



fell down, which after wafliing and ignition amounted to five 



grains. 

 Infoluble part (f) The remaining part that was left undiflx)lved by the 



^iiiron, can flic lye, appeared of a black-brown tinge. This, after 



wathing and expofure to red heat, weighed two grains, and 



was oxided iron. 



Hence, according to this analyfis, the fum of the conflituent 



parts of the ^a'o hundred grains of the red antique glqfs-pafie de- 



compofed, confifls of, 



Silex 



