218 P>'of' Renwick on Torrelite. [March, 



about half an hour, leaving a considerable part of the mass 

 undissolved, and but little altered in appearance. 



The muriatic solution being acted upon by tests showed, 

 among others, the following phenomena : 



(2.) With ferrocyanate of potash a copious blue precipitate. 



(3.) With ammonia a precipitate of a I'ich vermillion red. 



(4.) With carbonate of ammonia a reddish white precipitate. 



(5.) With hydrosulphuret of potash, a milky appearance, that, 

 subsiding, left a scanty brown precipitate. 



(6.) The compounds of cerium being soluble in excess of acid, 

 the uitro-muriatic solution was concentrated until the greater 

 part of the free acid had evaporated, and was then neutralized to 

 the point of nascent precipitation by carbonate of soda. 



(7.) A part of the liquor in No. 6 being diluted, crystals of 

 sulphate of soda were thrown in ; these, after some hours, were 

 dissolved, causing a white precipitate. 



(8.; To another portion of the concentrated and neutralized 

 nitro-muriatic solution (G) tartrate of potash was added, on 

 which a copious white precipitate ensued. The suspicion that 

 the substance contained cerium being thus confirmed, it was 

 subjected to a more strict examination, as follows : 



B. 



(1.) A mass weighing nearly an ounce, and containing a very 

 few small grains of the oxide of iron, was broken from the cor- 

 ner of one of the specimens. Weighed by means of a very accu- 

 rate hydrostatic balance, it appeared to have a specific gravity 

 of 3-25. 



(2.) This mass being first crushed into fragments in a steel 

 mortar, all the extraneous matter was carefully picked out with 

 a forceps ; it was then reduced to impalpable powder by long 

 grinding in an agate dish. 



(3.) Fifty grains of the powder were boiled for half an hour 

 in nitro-muriatic acid, the solution assumed a rich yellow colour, 

 and a considerable residuum was left, which, separated, washed, 

 and dried, had lost in weight exactly 27 grains, 



(4.) The insoluble portion (3) was then put into a silver cruci- 

 ble with 70 grains caustic potash ; water being thrown on, the 

 mixture was boiled, evaporated to dryness, and finally fused. 

 The fused mass was softened by water, and separated from the 

 crucible ; muriatic acid being then added, the solid matter 

 swelled up into a gelatinous mass. This w as evaporated to dry- 

 ness, being constantly stirred throughout the process, and after- 

 wards boiled for two hours in very dilute muriatic acid. The 

 whole was then thrown upon a filter, and carefully washed ; the 

 insoluble portion when dry was found to weigh 16'3 grains, was 

 white, with a faint and hardly perceptible tinge of rose colour. 



(5.) The nitro-muriatic solution and washings (3), and the 



