310 Notices respecting New Books. 



important articles in this branch of the science, those on Bile, Blood, 

 and Chyle may be mentioned. 



There are many other articles of a more purely chemical nature 

 which possess great value and interest. Among the number we 

 may mention particularly those on Combustion and Chemical Affinity. 

 In the latter article, the distinctive characters of chemical action are 

 first considered, then its different kinds, next an account is given of 

 the various investigations that have been made in order to determine 

 the laws which regulate its amount, and lastly the various theories 

 which have been propounded, as to the nature of chemical affinity, 

 are explained. Altogether this article forms the best treatise on 

 the subject with which we are acquainted. Nevertheless it is im- 

 possible to read it without coming to the conclusion that the ascer- 

 tained facts which throw any distinct light on the nature and mode 

 of action of the force which produces chemical action are very few 

 indeed : by far the most important is, no doubt, the constant quan- 

 titative relation subsisting between chemical action and other forms 

 of energy. For this part of the subject we are referred to the arti- 

 cles Heat and Electricity, where it will no doubt be fully discussed ; 

 but we think that it might also have been treated with considerable 

 advantage from a chemical point of view. 



The most complete exposition, with which we are acquainted, of 

 the principles to be adopted in fixing the atomic weights of the 

 elementary bodies, is Dr. Odling's article Atomic Weights in this 

 volume. The author there sets forth with singular clearness the 

 various arguments, physical as well as chemical, which bear upon 

 the subject ; and does not so much strive to illustrate the advan- 

 tages of a particular system, as to explain the grounds upon which 

 any logical system must be based. We do not, however, agree with 

 his conclusion that Gerhardt's scale of atomic weights affords a satis- 

 factory representation of the present state of knowledge ; on the 

 contrary, we think that the consistent application of the spirit of 

 Gerhardt's reforms would lead us now to go much further than 

 he did. 



Considering the very wide range of subjects included in this 

 volume, and the uniform excellence of the execution, so far as we 

 feel competent to form an opinion, it reflects the very highest credit 

 upon the editor, and cannot fail to raise his already high reputation. 

 Watts's ' Dictionary of Chemistry ' will doubtless long remain a 

 standard work, and one of the most valuable in our language. It is 

 from this conviction that we thought it worth while to indicate at 

 the beginning of this notice one or two points connected with the 

 issue of this volume, attention to which will, it may be hoped, 

 ensure even greater excellence in its successors. 



