Experimenls on Plattrtci. T25 



I dram and 24 grains, Iiad I employed the fame prodnft 

 \vith the addition of 4 ounces of nitric acid. Let us now 

 examine the confequences which may be deduced from thefe 

 refults. 



If we fuppofc that the firft mixture conld difTolve 8 drams 

 and a half of platina,tlic muriatic acid added mult have found 

 a fufficicut quantity of nitric acid to oxygenate it; but 4 ounces 

 of my muriatic acid not being able to diflbfve fo Itrong a 

 dofe of platina, it thence foliuus that, in the total produ«Sfof 

 the diftillation, there niuft have been prefent two ounces^ at 

 leaft, of the fame acid. Since 12 ounces of muriatic acid 

 were indeed employed in tiie third experiment to diflblve 

 17 drams of platina,' it is evident that to dilVolve the half of 

 this quantity, or 8', drams, 6 ounces of the fame acid would 

 have been required ; and iiiice we had in the receiver the 

 quantity of ii ounces of muriatic acid, there is no doubt that 

 there remained in the retort about 10: in a word, that thefe 

 ID ounces of acid at 15 degrees, ftrengthened bv the oxygen 

 of the nitric acid, can onlv diflblve 16 or 17 drams of black 

 crude plalina. 



Let us now proceed to a valuation of the nitric acid which 

 might be contained in the prodndl of our diftillation. 



It is feen by the third experiment that 12 ounces of mu- 

 riatic acid require not Id's than 4 ounces of nitric acid to 

 enable it to dilfolvc 17 dr;Tms of platina. There were there- 

 tore 2 ounces at leaft in the produA of our diltillation, fince, 

 with thcadiftanceof 4ounces of mnrialic acid ■^L^\<^Ql\, it could 

 have diifolved 81- drams of platina, or the half of 17. 



It thence follows, that there pafs into the receiver, durinn- 

 the whole eourfe of the diftillation made with the propor- 

 tions of the third experiment, nearly 2 ounces of nitric acid 

 ^^3.'>^ 'i"d an equal quanlil)- of muriatic at 15°, diluted in 

 <^ ounces i dram of water; 'which quantities, united, form 

 the produft, being 10 ounces i dram. It thence refults 

 alio, that the 17 drams were really dlllblvcd by 10 ounces of 

 munatic acid, oxygenated by the decompofttion of only a out 

 of the 4 ounces of nitiic acid employed. 5^hould it however 

 be aflced, on feeing this eltimatc, why 16 or 17 drams of 

 platina could not he diifolved in a mixture of jo ounces of 

 muriatic acid and 3 oiuices of nitric acid ? we rcjily, that the 

 heat neceftary to aflift the adion of this folvent may have. 

 loon changed the prc^portions of the compolition of the acid, , 

 as in the experiment ue have analyfed. 



In regard to the lirft acid, formed by the produdlofthe 



diftillation, it is cerlaiu that il contains 3, futlicicut quantity 



.? of 



