Notices respecting New Booh. SOS 



and in all mutual decompositions between bodies of this 

 class, similar circumstances appear to occur : thus there 

 are two combinations of mercury with oxygen, the black 

 and the red ; and one appears to contain twice as much 

 oxygen as the other. There are U\o known combinations 

 of iron with oxygen, the black and the red oxide of iron ; 

 and the oxygen in the first being considered as 2, that in 

 the second must be considered as 3; that is, 100 parts of 

 irou take ^9 parts of oxygen to become the black oxide, 

 and 43-3* to become the red. 



"The decompositions of compounds containing oxymu- 

 riatic gas, or chlorine gas by water, afford the best and 

 most intellisiible instances of double deccnnposition. If 

 equal volumes of light inflannnable air or hydrogen, and 

 chlorine be mixed together, and exposed to day-light, they 

 slowly act upon each other, no condensation takes place, 

 and they form an equal volume of muriatic ac d gas; so 

 that muriatic acid gas consists of hydrogen and chlorine in 

 equal volumes; and water, as has been before stated, consists 

 of two parts in volume of hydrogen, and one part in volume 

 of oxvgen. Now phosphorus and sulphur, and most of 

 the metals, combine with chlorine, and form peculiar com- 

 pounds, many of which are decomposed by water, and ihe 

 results are phosphorus, sulphur, or the metals combined 

 with oxygen, and muriatic acid; and the oxidated com- 

 pounds formed, are the same as those produced in other 

 ways ; and it is evident, that the quantity of hydrogen 

 given to the chlorine to form the acid, must be exactly in 

 the ratio of the oxygen added to the inflammable substance 

 or the metal : thus, phosphorus burnt in chlorine in excess 

 forms a white volatile substance, wliich I have named 

 phosphoranee. When water is added to this, phosphoric 

 and muriatic acids are fornied, and there are no other pro- 

 ducts. 



" 10. As in all well known compounds, the proportions 

 of the elements are in certain definite ratios to each other; 

 it is evident, that these ratios may be expressed by num- 

 bers ; and if one number be employed to denote the smallest 

 quantity in which a bodv combines, all other quantities of 

 the same body will be nudtiples of this number ; and the 

 smallest proportions in which the undecomposcd bodies en- 

 ter into union being known, the constitution of the com- 

 pounds they form may be learnt, and the element which 



• These rcjiilts t have obtained very nearly, namely, 23 and -13 ; and 

 they difl'er very liule iroai those of Mr. Hassenfratz, Dr. Thomson, and 

 Mr. Bcrzeliut. 



unites 



