12,6 Experintents on Platlha, 



of nitric acid to oxygenate the 3 ounces of muriatic acid 

 which we found in it : but the great quantity of water in 

 which they are diluted deftroys all their aAion; and if the 

 addition of 4 ounces of nitric acid redorcs to them fome 

 ftrength, it is only, in all probability, becaufe that quantity 

 of acid augments, to a certain degree, the concentration of 

 the muriatic acid. 



From thefe data let us try to determine what is the largeft 

 quantity of platina that can be difTolved in nitro-muriatic acid 

 prepared according to the proportions above indicated. 



To diflblve firft the 17 drams and 54 grains, and then thd 

 8 drams and 3a grains, making together 26 drams and 14 

 grains, we euiplnyed 12 ounces ot muriatic acid and 4 of 

 nitric acid, and afterwards 4 ounces of the former, that is to 

 fay, 20 ounces of mixture in the whole. Calculation (hows, 

 ncgleiiling the 14 grains of platina, more or Icfs, that only 

 5 pounds II ounces* of nitro-muriatic acid are req'.iifite to 

 diffolve a pound of black crude platina, which is that I em- 

 ployed in thefe experiments. If we confult the cheinilts, we 

 fhall find that the greater part of them have fixed at 16 parts 

 the quantity of nitro-muriatic acid which miift be employed 

 to diiTohe one of platina. If I am not miftakcn, Lewis and 

 count Sickingen were the only perfons able to didblvc it with. 

 8 parts of fuivent. But they were obliged to perform two 

 operations to diffolve that quantity' White crude platina is 

 the kind moll foluble; for I find, in a note, that a pound of 

 nitro-nuiriatic acid, compofed according to the proportions 

 indicated, diliblved 18 drams and 24 grains. 



XVI. Solution of Fl'Ut'ma by the Means of a Nitro-muriat'ic 

 Acid compofed of JMtr/c yL-idf at '^l^ and I^lanne Salt. 



Bergman found thai an acid compofed in this manner, dif- 

 folved platina exceedingly well. It will be feen by the fol- 

 lowing experiments that, in an operation on a great fcale, 

 this fblvent may be preferred to thofe compofed with pure 

 acids. To be able to difcover the mod advantageous pro- 

 portion of acid and I'alt, I made a feries of experiments, but 

 I {hall e;ive an account of thofe only which can ihrov/ light 

 on folutions of this nnture. As the method of employing 

 this kind of nitro-muriatic acid is not different from that 



'* ^Vc are here, no doubt, to underftand the Spaniili pound, which is 

 nearly a feventeenth iefs than the Frencli pound ; bat as ic is divided into 

 16 ounces, or izS drams of 72 grains, the proportions remain the fatr.e. 



+ The degrees here mtntioncd arc tttofs ot" Haamc's areometer ; 31'* 

 indiccitc afpecific gravity of I'i'r}. 



followed 



