76 Notice of some recent additions to Chemistry. 



solution in alcohol and slow crystallization, the acid was obtained in 

 tolerable large crystals with a shade of green, but the crystalline form 

 was not sufl&ciontly regular to admit of definition. Some portion was 

 obtained in small crystals of such purity, it was thought, as to admit 

 of analysis, but it was not perfectly pure, as it only gave 69 per cent 

 of carbon and 10G3 water. We formed also the nitro-lithofellic acid, 

 by the action of nitric acid on lithofellic acid, but not in sufficient 

 quantity for analysis. 



The chemists of the Continent who have hitherto adopted the atomic 

 weights determined in Sweden, without calling their accuracy in ques- 

 tion, have lately had their attention drawn to this important subject 

 by Dumas, since his visit to this country, who, followed by others, has 

 established the accuracy of the following atomic weights, determined 

 more than twenty years ago in the Glasgow University laboratory: — 



Chlorine, 4*5 



Hydrogen, -125 



Azote, 1-75 



Carbon, '75 



Potassium 5* 



Calcium, 2-5 



Silver, 13-75 



Lead, 13* 



It may not be an uninteresting fact in the history of atomic weights, 

 to state, that in 1813, or twenty-nine years ago, (Annals of Phil., iv. 

 42,) Dr. Thomson deduced -751 as the atomic weight of carbon, from 

 the specific gravity of carbonic acid, confirmed by his analysis of 

 defiant gas. The atomic weight of azote, in the same year, he also 

 deduced from nitrous gas as -878, almost the half of the present 

 number, for -878 X 2 := 1*756. It was from these numbers as a start- 

 ing point, that Dr. Prout was first led to infer the theory of multiple 

 atoms. R D T 



Since the preceding report was read, a communication has been 

 made by Fremy to the academy of Paris, in which he shows, that 

 besides iron and tin, many other metallic oxides act the part of 

 acids, and, what is curious, that their capacity of saturation increases 

 with the quantity of water united to them; their electro-negative 

 properties are lost when they are anhydrous, (L'Institut. 468.) He 

 has obtained a crystallized aluminato of potash, consisting of an atom 

 of each and two of water. Bizincate of potash is obtained in long 

 needles by treating oxide of zinc with potash, and a little alcoliol. 

 Bismuthate of soda is obtained by heating oxide of bismuth with soda. 

 Plumbites are the result of the action of protoxide of lead on alkalies, 

 a,ud plumbates of the brown oxide. Minium Fremy considers a plum - 

 bate of protoxide of lead, analogous, therefore, to the chromate of 

 chromium described by Dr. Thomson in 1824. 



BELL AND BAIff, PRINTERS, GLASGOW. 



