412 Miscellaneous Intelligence. 



duced by arsenic, could not be distinguished by colour or ap- 

 pearance from it. — Silliman's Jour, iii.p. 355. 



7. On the detection of Arsenic in Ores ofAntimomj. — The fol- 

 lowing is the process of M. Serulas, by which he detects arse- 

 nic in antimony. The antimony, or its oxide, is mixed with 

 cream of tartar, and heated in a close crucible : in this way an 

 alloy of the antimony with potassium is formed. The alloy is 

 then placed under a bell-glass filled with water, and a large 

 quantity of hydrogen is soon liberated. This, when burned in 

 a narrow glass jar, deposits a brown pellicle on its sides, if the 

 antimony contains arsenic, but no pellicle is produced if arsenic 

 be not present. Very small quantities may be detected in 

 this way. 



8. Berzelius on the Oxide of Platinum and Gold. — After re-, 

 marking on the numbers given for the oxides of platinum by 

 Mr. Cooper and Dr. Thomson, M. Berzelius proceeds to de- 

 scribe the process he now adopts to obtain these numbers accu- 

 rately. The muriate of platina and potassa being a neutral 

 compound, a portion of it was well washed and dried ; it 

 was then anhydrous, and by heat gave off chlorine, without 

 any trace of water ; so that it may be concluded to be a double 

 chloride of platinum and potassium, x 2.251 grains were slowly 

 heated in a current of dry hydrogen as long as muriatic acid was 

 formed. It lost .Q5 of a grain in weight, and the residue washed 

 left .898 of platinum undissolved. It was therefore composed of 



Chlorine . .650 



Platina . . .898 



Chloride of potassa . .703 



In the tables of M. Berzelius the numbers are such that, if 

 calculated, it will be found that the platinum contains twice as 

 much chlorine in the above compound as the potassium. An 

 atom of muriate of potassa is 1865.13, and 2 atoms of mu- 

 riate of platina are 4201.6, so that the compound atom would 

 weigh 6066.19. This would give in 2.251 grains of the sub- 

 stance .657 chlorine, .898 platina, and .696 muriate of potassa, 

 which is nearly accordant with the experiment above. 



The same results were obtained with the muriate of soda and 

 platinum. This salt contains 1 atom of muriate of soda, 2 atoms 

 muriate of platinum, and 12 atoms of water. 



M. Berzelius still retains his opinion of the number for gold, 

 or the weight of its atom (2486.) He adds an experiment in 

 which he reduced it by phosphorous, but says it is not so pre- 

 cise as the reduction by mercury, consequently it adds nothing 

 in proof of the correctness of the numbers given. M. Pelletier, 

 it will be remembered, gives the number of gold as 2993. 



