Royal Instiiut ion. 131 



The angle in all of them he found some degrees more than 

 M, Haiiy ; and also that each had a distinct measure, which 

 in whole numbers may be stated at 105", 106°, and 107°. 

 Hence he was led to the very important conclusion, that a 

 difference in constituent principles docs in every case produce 

 a difference of primitive form; that the exceptions to this 

 genera! position are entirely owing to errors in our crystal- 

 lographica! operations, and that the crystallogical theory is 

 more true to nature than even its author had supposed. 



Feb. 13. A paper by Mr. John Davy, communicated by 

 his brother Mr. Davy, was read. MM. Gay-Lussac and 

 Tlienard and Mr. Murray have asserted that there is no ac- 

 tion between gaseous oxide of carbon and oxymuriatic gas 

 or chlorine, v/hcn they are exposed to sunshine. Mr. John 

 Davy states in this paper a very different result — that the two 

 gases combine and become condensed to half their volume, 

 and form a peculiar new elastic fluid possessed of acid pro- 

 perties. He gives an account of the nature <md combina- 

 tions of this substance, which neutralizes four times its vo- 

 hin)e of ammonia, and forms with it a peculiar salt; it 

 is not disengaged from ammonia bv acetous acid, iior by 

 sulphmeous ac.d, and it is decomposed by the metals into 

 gaseous oxide of carbon and chlorme, so that its constitu- 

 tion is established both by analytical and synthetical ex- 

 periments. 



Feb. 20. Another paper bv Mr. John Davy was com- 

 municated to the Society by Mr. Davy. It related to the 

 conibinaiions of certain metals with chlorine and oxygen, 

 and contained some general views on the theory of definite 

 proportions. The pure combinations of metals with chlorine 

 resemble in many respects oxides ; they are non-conductors 

 of electricity, njanv of them are very volatile, and they forrn 

 muriates by decomposing water. Mr. John Davy describes 

 two combinations of copper and chlorine, one containing 

 twice as much chlorine as the other. Two of iron and 

 chlorine, one containing half as much as the other. And 

 two of tin and chlorine, of which the second contains double 

 as much chlorine as the first. Bismuth, antimony, arsenic, 

 zinc, lead, he has been able to combine with chlorine in 

 one proportion onlv. Between the oxygen in oxides and 

 the chlorine in these combinations, the rate is as ~rb to 

 33-6. Many of these combinations with chlorine conibjne 

 with oils : and Libavius's liquor, the compound of chlorine 

 ;ii)d tin, inflames in acting upon oil of turpentine. As thy 

 oxides are soluble in acids, so likewise arc these compound? 

 in an acid that they cannot decompose. Corrosive sub- 

 liijulc forms a particular salt, by combining wiih muriatic 

 J <■?. acid; 



