274 ANALYSIS OF THE ROE OF fISHfiS. 



6. Heated in a platina crucible, it first hardens, then sof- 

 tens, and at length melts in great part. Yellow fumes are 

 emitted, which have the acrid smell of animal fats. 

 T|iecoalcotT. ^ The coal of the roe, being washed with warm water, 

 communicates to it a vcri/ decided acidity. This solution 

 gives a precipitate with alkalis: if it be evaporated to dry- 

 ness, and the residuum tieatcd with water, a white substance 

 separates, consisting of the phosphates of lime and magne- 

 sia : if ammonia be added to it, amtnoniaco-magnesiau 

 phosphate and phosphate of ammonia are obtained. 

 •*hich is the Water therefore extracts from the coal of the roe free 

 ji oip one, phosphoric acid, and a little phosphate of lime and of magne- 

 sia. 



The phosphoric acid obtained certainly did not exist in 

 the roe, for this is not acid. On the other hand the roecon- 

 tains no volatile alkali, that can be made evident to the 

 senses. Now as the phosphate of ammonia is the only salt, 

 that can yield phosphoric acid by the means of heat alone, 

 and formed we must conclude, that this acid is formed during the combus- 

 dunng the ^- ^^ ^j^^ which is a very remarkable fact, and altoge- 



combustion. 



ther 



new. 



Roe calci-ned Sect. II. Combustion and calcination, of the roe in an open 



fire. 



Perforated the 1. One hundred and seventy-eight gram. [2748 grs.] of 

 platina cruci- fi-esh soft roe yielded 7'8 gram. [120 grs.] of coal. This 

 coal, strongly calcined in a platina crucible, grew red, and, 

 perforated the crucible. The metal was rendered brittle. 

 Yielded phos- 2. The aqueous lixivium of the coal was acid. On eva- 

 phate of lime, poration it let fall 45 centig. [7 grs.] of phosphate of lime. 



The lixiviated coal weighed only 5 gram. [77 grs.] 

 Phosphoric 3. The lixivium deprived of phosphate of lime, andsatura- 



acid, ^^^^ ^\f\^ volatile alkali, yielded 5 gram. [77 grs.] of dry phos- 



phate of ammonia. 

 nnd phosphate 4. This phosphate of ammonia contained a little phos- 

 of magnesia, p^g^-g ^f magnesia; for, being heated before the blowpipe, 

 it yielded a transparent pearl, which became opake on cool- 

 inf, and was not wholly soluble in water. 

 Phosphorus 5. On distilling 5*6 gram. [86-5 grs.] of tbis'^phosphate of 



formed from ammonia with I gram. [15-4 grs.] of charred cork in a 



coated 



