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XVII. observations 07i the Relation of the Law of Defiiiite 

 Proportions in Chemical Combination, to the Constilntion of 

 the yields. Alkalis, and Earths. By John Murray, M.D. 

 Fellow of the Royal Collsoe of Physicians, of the Royal So- 

 ciety of Edinburgh, the Geological Society of London, (5#c., 

 Lecturer on Chemistry, and Materia Medica and Pharmacy.^ 



Xhe law that every body enters into chemical combination in 

 a certain equivalent weight to others, and that when it combines 

 in different proportions with another, these proportions have a 

 -simple arithmetical ratio, is perhaps the most important that has 

 hitherto been discovered in the science of chemistry. It is now 

 so far established, notwithstanding some difficulties which attend 

 it, that when a vievv of the constitution of an extensive series of 

 chemical compounds is brought forward, different from what had 

 hitherto been proposed, it is incumbent to show that it is con- 

 sistent with the operation of this law ; and if just, this may dis- 

 play relations not before observed, and may obviate objections 

 which have arisen from a different view. It is from these consi- 

 derations that I submit the following observations on the appli- 

 cation of the law of definite proportions to the theory which I 

 have proposed of the chemical constitution of the acids, alkalis, 

 and their compounds. It necessarily leads to considerable modi- 

 fications of these applications; and the conclusions which these 

 afford, if I am not deceived, afford proofs of the truth of the opi- 

 nion I have advanced, and lay open some new views. The sub- 

 ject is at the same time so extensive, as to have relations to 

 nearly all the details of chemistry. 



In the preceding paper f I remarked, that the relations in the 

 proportions of oxygen and hydrogen forming the supposed por- 

 tion of combined water in the acids, will probably be those of one 

 or both of these elements directly to the radical. It remained 

 to be determined liow far this is just. 



Sulphur affords the best example for illustration, as its com- 

 binations with oxygen and hydrogen are capable of being accu- 

 rately determined. 



Sulphur and oxygen are held to combine in two definite pro- 

 portions, forming sulphurous and sulplmric acids. In the first, 

 100 parts of sulphur are combined with 100 of oxygen; in the 

 second, 100 are combined v.-ith 150 of oxygen, forming what is 

 called the real acid, with which are further combined 56'7 of 

 combined water, the entire compound, constituting the acid in 

 the highest state of concentration, (1*85 of specific gravity) in 

 which it- can ije procured in an insulated form. 



This constitution of these compounds appears at first view in 



* Communicated l)v the Author. 



t See Phil. Mag. vol. 52. p. 107 and 195. 



opposition 



