Notices respecting New Booh. 377 



As a specimen of the style of the work, and the happy man- 

 ner in which the new facts are brought together and classed, so 

 as to lay before the reader, in a condensed yet perspicuous detail, 

 their application by their respective authors, and others who have 

 illustrated them, we select a part of the article "Jffinihj," 



After noticing BerthoUet's now exploded opinion, that it is 

 the tendency of Chemical Affinity to combine bodies in all pro- 

 portions ; and also the opinion of Richter, Proust, and other 

 eminent chemists, supported by a daily increasing body of ex- 

 periments, that substances unite in proportions which are ren- 

 dered definite by the sole operation of their mutual affinity, they 

 notice Mr. Dalton's most important rule on this subject, that 

 " where two bodies combine in different proportions, if the quan- 

 tity of one of them be assumed as a fixed number, the propor- 

 tions of the other body that unite to it are in the simplest possible 

 ratio to each other, being produced by multiplying the lowest 

 j^roportion by a simple integral number, as 2, 3, 4, &c." — and 

 then give the following illustration and application of the doc- 

 trine and the rule : — 



" Thus, for example, if a metal can combine chemically wich 

 different proportions of oxygen, if 100 of the metal take 9 of 

 oxygen for the lowest degree of oxygenation, all the other de- 

 grees will be in the proportion of 100 of metal to twice 9(18) 

 of oxygen; or 100 of metal to three times 9 (27) of oxygen; or 

 100 of metal to four times 9 (36) of oxygen, &c. &c. A reason 

 for this simplicity in the ratio of binary compounds may be 

 found in the general principle assumed by Mr. Dalton, which is, 

 that in all cases the simple elements of bodies are disposed to 

 unite atom to atom singly, or if either is in excess it exceeds by 

 a ratio to be expressed by some simple multiple of the number 

 of its atoms. 



" Hence, from the relative weights of the constituent parts of 

 a compound, Mr. Dalton infers the relative weights of the ulti* 

 mate particle or atom of each of these parts ; and, this being 

 found, the number of atoms of each constituent which enters into 

 the formation of the compound particle is also deduced. 



" Thus (taking a compound of two constituent parts A and B, 

 as the simplest case) if its elements are found by experiment to 

 unite in the proportion of 5 of A to 7 of B, it is inferred by Mr. 

 Dalton that the numbers 5 and 7 express the comparative weight 

 of an atom of A and B respectively. And these elements, though 

 uniting in several proportions, will yet be found by experiment to 

 be confined to eitlier 5 A to \A, 21, 2S, &c. of B, which is, one 

 atom of A to 2, 3, 4, &;c. atoms of B ; or conversely it will be 

 7 B to 10, 15, 20, &c. of A, which is one atom of B to 2, 3, 4, 

 .&c. atoms of A. It is essential to the consistency of this system, 



therefore, 



