1815.] Experiments upon Green Uran Mica. 283- 



dried, collected, and ignited. It was weighed whilst still warviy 

 and it amounted to 74'9 grains. It was of a light yellow colour ^A). 

 This I had reason to consider as oxide of uranium ; but subsequent 

 experiments proved that this amount must be subjected to some 

 slight corrections. 



II. The ammoniacal solution of copper, with the water of edul- 

 coration, was evaporated gradually to dryness ; * and with a view of 

 ascertaining whether it contained any of the oxide of uranium, I 

 redissolved the mass, which remained, in nitric acid, and treated 

 the solution, as Ijefore, with ammonia. A very small quantity of 

 yellowish-white matter remained undissolved, which after ignition 

 = 0-2. It was oxide of uranium, and must therefore be added to 



The ammoniacal solution of copper was now evaporated to dry- 

 ness, again dissolved in niuic acid, and boiled witii liquid potash, 

 which precipitated ihe copper in the state of oxide, which after 

 ignition = 7'G5. 



III. The 7-1*9 gr. of supposed oxide of uranium were moistened 

 with distilled water, and some test sulphuric acid was gradually 

 poured upon the mass, and the vessel containing it was placed in 

 warm sand. The mass soon became dark green, and resembled in 

 consistency, as well as in intensity of colour, the pigment called 

 ^ap-grcen, when suspended in water. What the acid had not dis- 

 solved appeared gelatinous ; and when warm water was poured upon 

 it, and it was stirred with a glass rod, it separated ioto lumps some- 

 what resembling spermaceti. They were encompassed by a greenisji' 

 fluid, and required repeated effusions of sulphuric acid for their 

 solution. A grecuish-white matter resisted the acid. It was care- 

 fully collected, dried, and ignited ; it = O-G, treated with carbonate 

 of soda, in a [)latinum crucible, and subsequently with nitric acid, 

 Sif. It proved to consist chiefly of oxide of uranium, with a very 

 • mall portion of oxide of lead, too sn:all, indeed, to admit of being 

 accurately weighed, f Upon dropping ammonia into the solution of 

 tlu' oxide of uranium, which 1 had eliectcd by means of sulphuric 

 acid, I was surprised to find that it was tinged blue, indicatinij 

 thcrcl)y the (irescnce of copper. The same process with ammonia, 

 before detailed, was repeated, except that at last the co[)per was 

 dissolved in sulphiuic acid, and separated in a metallic siaie by a 

 cylinder of zinc. The copper thus obtained, after having been 

 iduleoiated, and shaken with very dilute ntuiatic acid, and care- 

 fully dried, weighed 0-5, which, with the accessioti of oxygen in 

 the ratio of 25 per cent., is equivalent to G-2 of oxide. The 

 71 'O grains of supposed uran oxide must then iur<- be diminished 

 by the subtraction of OG'2 of oxide of copi)er = 74-28, which. 



• In ;i fiirnicr rxpiriineiil U|i<iii 100 s,t. i)f tliiii miner.il I rvopnralod the 

 niprruiis .-iiniiiciriiac li> drMif^s, ami <>\|)ok(<I ilic div iiuiss la a ri-il ncit, bull 

 toiild nut dflcc-t the !.Ii«;l(lf.t liacc I'illier uT poi ••■U or suda. 



t In my furnier aualysi* I delected a bmall quantity of oxidr of Irad also. 



