222 Mr. Children on the Analysis of Torrelite. [March^ 



on cooling, and is ultimately reduced to a yellowish tint ; by 

 flaming, the glass becomes enamel white. In the reducing 

 flame it loses its colour."* That these characters are accurately 

 given, I can vouch from experiment. 



A portion of the mineral in fine powder was digested in nitro- 

 muriatic acid to dryness. The dry mass was redissolved in 

 water, with the addition of a little muriatic acid, and a few drops 

 of nitric. A part remained undissolved, which on examination 

 proved to consist of silica with a little oxide of iron and oxide of 

 manganese. This being separated by the filter, ammonia was 

 added to the clear solution, AVhich threw down an abundant 

 dark' red precipitate, {a). The whole was thrown on the filter, 

 and the ammoniacal solution set aside. On standing a few 

 hours, it deposited a portion of pure oxide of manganese ; and 

 on the addition of oxalate of ammonia, afforded an abundant 

 ■white precipitate, which v/as found to consist merely of oxalate 

 of lime with a considerable quantity of oxalate of manganese. 



The dark red precipitate (o) was redissolved in muriatic acid 

 with a few drops of nitric acid, the solution carefully neutralized 

 by ammonia, and an excess of oxalate of ammonia dropped into 

 it. At first that reagent occasioned no precipitate, but after a 

 large quantity of the oxalate had been added, the solution 

 became turbid, and on standing deposited a small white precipi- 

 tate. This was separated by decanting oft' the supernatant 

 fluid and well washed. On examination it proved to be nearly 

 pure oxalate of manganese, for being heated in a platina cap- 

 sule over the spirit lamp to redness, it left a dark brown sub- 

 stance, which gave with soda and nitre, before the blowpipe, an 

 opaque dark green globule in the oxidating flame, and with 

 borax a transparent one of a beautiful amethyst colour, which 

 disappeared when heated in the reducing flame. 



Ammonia added in excess to the solution from which the last 

 precipitate had been separated, threw down a large quantity of 

 red oxide of iron mixed with a little manganese, and on pouring 

 in a solution of prussiate of potash to the ammoniacal liquor, 

 previously filtered, a considerable white precipitate of prussiate 

 of manganese was immediately formed. 



As my object was merely to ascertain whether oxide of cerium 

 be present in the mineral or not, the quantities of the several 

 precipitates were not attended to ; the quality of each, however, 

 was carefully examined, and no trace of cerium could be detected 

 in any of them. 



A portion of cenV^, similarly treated, instantly gave an abund- 

 ant precipitate of oxalate of cerium, on adding oxalate of ammo- 

 nia to the nitro-muriatic solution, previously neutralized by 

 ammonia. 



• The U»e of the Blowpipe in Chemical Analysis, &c. p. 100. 



