477 



than half that of chlorine, and so little exceeding that of oxygen, 

 that those who would suppose it to contain oxygen combined with 

 an inflammable base, must suppose the base to be less than one 

 twentieth part of the oxygen with which it combines. 



Catalogue of North Polar Distances of Eighty-four principal fixed 

 Stars, deduced from Observations made with the Mural Circle at the 

 Royal Observatory. By John Pond, Esq. Astronomer Royal, F.R.S. 

 Read July 8, 1813. [Phil. Trans. 1813,^. 280.] 



A Synoptic Scale of Chemical Equivalents. By William Hyde 

 Wollaston, M.D. Sec. R.S. Read November 4, 1813. \Phil. 

 Trans. 1814, p. 1.] 



The design of the scale here proposed by the author is to save 

 chemists the labour of many troublesome computations in estimating 

 the ingredients of neutral salts, and the reagents and precipitates by 

 which these ingredients might be ascertained. 



For though certain laws to which chemical union is subjected 

 have of late been discovered, and have enabled chemists to determine 

 with greater precision than formerly the composition of bodies sub- 

 mitted to be examined, and to express numerically the relation of 

 the several elementary chemical substances to each other; never- 

 theless the computations requisite for applying these results to many 

 objects of inquiry are frequently attended with considerable trouble. 

 The author briefly sketches the history of proportional chemistry, 

 beginning with Bergman, who, perceiving that the same acid united 

 to the same base, always in the same proportion, took pains to 

 ascertain the composition of various salts. Kirwan followed the 

 same line of endeavour to a greater extent, with a view to determine 

 the proportions of various acids to different bases, as questions in- 

 dependent of each other. To these succeeded Richter, who gave con- 

 nection to the subject by observing a new relation that had escaped 

 the notice of Bergman, Kirwan, or any of his predecessors. They had 

 observed only the constancy of the proportion of the same acid 

 to the same base ; Richter observed, further, a fixed relation of acid 

 to acid : namely, that when the proportional quantities of any two 

 acids, that are each sufficient to saturate a given quantity of any one 

 base is determined, the same proportional weights of these acids will 

 also saturate equal quantities of any other base ; and consequently 

 that if any quantity of sulphuric acid be assumed as standard, then 

 equivalent quantities of all other acids may be conveniently expressed 

 by fixed numbers, adapted to each; and the several quantities of 

 different alkalies and earths that would each saturate the standard 

 quantity, might also be represented constantly by corresponding 

 numbers. 



The observation of other proportions, which are simple multiples 

 of the preceding, by Mr. Dalton and others, are noticed as affording 

 an important correction of the best analyses ; but it is observed that 



