of Sciences of tlie Institute of France. 33 1 



the precediugj of a deep green ; which M. Dulong regards as a 

 simple mixture of nitrous acid, and another acid in which the 

 proportion of nitrous gas is much greater. 



M. Dulong has also investigated the proj)ortions in which 

 oxygen combines with phosphorus in the formation of acids. 

 Hitherto only two acids have been recognised, but his researches 

 have led him to think that four exist. 



The first in which the least of oxygen enters is obtained by 

 throwing in water an alkaline phosphuret. The phosphurctted 

 hydrogen is disengaged, and the oxygen of the water forms with 

 the remaining phosphorus an acid which continues combined 

 with the alkali, but which is expelled by sulphuric acid. M. Du- 

 long terms it hypophasphorus, but he believes that its radical is 

 in part composed of hydrogen. 



A second acid, to which M. Dulong transfers the name of 

 phosphorous, is obtained by decomposing water by a combination 

 of chlorine and a minimtmi of phosphorus, a decomposition from 

 which two acids result ; viz. hydrochloric or muriatic acid, and 

 this which M. Dulong calls phosphorous acid. M. Dulong states 

 it to be composed of 100 parts of phosphorus and nearly 75 of 

 oxygen. 



The third acid is that which is produced by the slow com- 

 bustion of phosphorus in air. It decomposes when saturated 

 with phosphoric acid and with phosphorous acid, and gives at 

 once phosphites which are more soluble, and phosphates which 

 ' are less so. M. Dulong does not regard it as a simple mixture, 

 but rather as a combination of these two acids, somewhat re- 

 sembling saline combinations, and in which the phosphorous acid 

 •serves as a base. According to that opinion, he proposes to 

 name it phosphatic, in order to recall the analogy which it bears 

 to the phosphates. 



The last term of oxygenation is ph' sphoric acid : the propor- 

 tion of phosphorus to oxygen is here lOO to 124. It is obtained 

 by the (juick combustion of phosphorus, or from the decom- 

 position of water by the chloruret [chlorure) of phosphorus, and 

 in many other ways. It is identically the same with that which 

 is extracted from the bones of animals. 



Three Dutch chemists, Messrs. Van Maruni, Deyman,and Paets 

 Van Trtjostwick, made known in 1796 a gas composed of hydro- 

 gen and carbon, which they named ulefant gas, on account of 

 the siu'^ular property it possessed of forming an oily liquid by it« 

 mixture with oxygenated muriatic gas. According to the theory 

 which then prevailed respecting oxygenated muriatic gas, it 

 might have been believed that the oxygen united itself to the 

 carbonctted hydrogen, and produced thus a sort of oil : but now 

 tHat we have come to regard this gas as a simple body, to which 



Sir 



