350 Scientific Intelligence. 



Claubry has shown, what was known previously, that a solution of the 

 chloride of lime, or of soda, is completely decomposed by a current of car- 

 bonic acid ; and his observations leave no doubt, we conceive, of the accu- 

 racy of the views of Iff. Gay-Lussac. — Abstract from the Ann. de Chimie 

 et de Physique, vol. xxxiii. 



15. On a new mode of preparing Carbonic Oxide Gas. By M. Dumas. 

 — This method is founded on a fact originally noticed by Dobereiner, that 

 oxalic acid is converted into carbonic acid and carbonic oxide gases by 

 digestion in strong sulphuric acid, which unites with the water of crystal- 

 lization. The process of M. Dumas consists in mixing the binoxalate of 

 potash with five or six times its weight of concentrated sulphuric acid. 

 The mixture placed in a glass vessel and heated, yields a considerable 

 quantity of a gas composed of equal measures of carbonic acid and carbo- 

 nic oxide ; and by absorbing the former by means of potash, the latter is 

 procured in a state of perfect purity. The theory of the process is ob- 

 vious. The sulphuric acid unites both with the water and base of the 

 salt ; and the free oxalic acid being unable to exist in the anhydrous state, 

 is decomposed. M. Dumas proposes this process for testing the purity of 

 the binoxalate of potash. In fact, the bitartrate yields by similar treat- 

 ment carbonic oxide, sulphurous acid, carbonic acid, and the residual 

 liquid becomes black, from the deposition of charcoal. The pure binoxa- 

 late, on the contrary, never gives sulphurous acid, and the solution re- 

 mains colourless, and perfectly limpid. — Ann. de Chimie et de Physique, vol. 



16. New Theory of Nitrification. By M. Longchamp. — It is well known 

 that animal matters form a constituent part of the nitre beds employed in 

 France and other parts of the continent for the production of saltpetre ; 

 and it is commonly supposed that the nitric acid so formed, proceeds from 

 the nitrogen of the organic bodies uniting with the oxygen of the atmo- 

 sphere. This is the theory embraced by Lavoisier, and which has for 

 many years been adopted without question. M. Longchamp, however, 

 has succeeded in throwing a doubt on the accuracy of this doctrine. He 

 has adduced a considerable variety of facts, which prove that nitric acid 

 is generated under circumstances when its production cannot be attributed 

 to the presence of organic remains ; that it is formed spontaneously in sub- 

 stances in which neither animal or vegetable matter is present. He finds 

 that the sole conditions necessary for the formation of nitric acid, are po- 

 rous earthy substances containing carbonate of lime, moisture, and access of 

 air. M. Longchamp maintains, as can scarcely be doubted in such instances, 

 that both the elements of the acid are derived from the air, and that water 

 favours the union of the gases by dissolving them, and thus presenting them 

 to each other in a fluid state. Tufa, chalk, and porous carbonate of lime 

 in general, favour the action in two ways, first, by absorbing air and water ; 

 and secondly, by presenting a base which solicits the formation of nitric 

 acid. M. Longchamp believes that similar changes occur in the ordinary 

 nitre beds. — Ann. de Chimie et Physique, vol. xxxiii. 



An ingenious extension of this theory has been made by Mr Graham 



