On some Combinations of Platina. 333 



Barometer 30". Thermometer 60" Fah. 



Experiment 1. — 9*3 grains of dry sulphate of platina 

 were heated to redness in a small retort over mercury, and 

 furnished the following results, 



grains. 



Metallic platina 6- 100 



Oxygene gas £'2 cubical inches — 0'748 



Sulphureous acid gas 0-25 cub. in. 0'170\ . 

 Sulphuric acid about 2-2S2J 



9-300 



Barometer 30". Thermometer GO". 



Experiments. — 18-5 grains of sulphate of platina were 

 tkconipounded as in the preceding experiment, and afforded 



grains. 



Metallic platina 12-15 



Oxygene gas 4"42 cub. in. = 15(i 

 Sulphuric acid about 4* 85 



18-50 

 This experiment was made over distilled water, with a 

 ■view to ascertain the quantity of sulphuric acid by muriate 

 of barytes ; but as the gas was examined, and dust from the 

 charcoal entered the water, much confidence could not be 

 placed in the results. — 10-5 grains of sulphate of barytes 

 were obtained, which indicates only 3-57 grains of sul- 

 phuric acid. The sulphureous acid gas absorbed by the 

 water would also interfere in calculations of this kind. 



Barometer SO". Thermometer GO". 



Experiment 3. — 15-45 grains of ?ulpha1e of platina were 

 decomposed over dry mercury, as in the first experiment, 

 and furnished the following products : 



grains. 



Metallic platina 10-10 



Oxvgcne gas 4-2 cub. inches = 1*42 



Siilpliurcous acid gas 0-35 cub. inch, and") 



sulphuric acid about . . J 393 



15-45 

 As the sulphureous acid gas obtained in the preceding 

 experiments must be conceived to. arise from the decompo- 

 sition of the sulphuric acid, it may he disregarded in the 

 caltula;ions. — Ft)r wlien the platina and oxygene, in a given 

 weight of the sulphate, are known, the remainder may 

 faiily be presumetJ to be acid, or acid and water. Now, 

 tliough my expermients do not necessarily preclude the 

 Vol .40.' No. 175. A'oy. 1812. Z presence 



