REVIEWS 



To the Editors, SCIENCE PROGRESS 



In asking for an opportunity of dealing with certain points of the review of my 

 Text-book of Inorganic Chemistry in the January number of Science Progress, I 

 desire in the first instance to express my thanks for the liberal amount of space 

 devoted to the consideration of my book. In so far as the criticisms express the 

 personal opinions of the reviewer, I have no comments to offer, being content to 

 leave the question of their justification to the judgment of others. The review 

 contains, however, certain serious misstatements of fact and I request that the 

 same prominence may be afforded to the corrections as was given to the original 

 statements. 



The criticism of the chemical part of the book is as follows : 

 "... In dealing with the interaction of nitric acid and metals not one word is 

 said of the work done by Russell, Veley and others showing the part that is 

 played by nitrous compounds. Under ' Modern Methods of Writing Complicated 

 Equations,' printed in Clarendon type, we have the following choice morsels : 



" ' An equation such as that representing the action of nitric acid on copper can 

 readily be written in stages. In such a case it is perhaps simplest to assume that 

 the oxygen of the nitric acid is used up in converting the metal to oxide, the latter 

 then uniting with more nitric acid to form the nitrate. As a preliminary to writing 

 the equation, the stage to which the nitric acid is reduced must be determined 

 experimentally and the formula of the nitrate must be known. The steps in the 

 action of nitric acid on copper are as follows : 



(i) 2HNO3 = H,0 + 2NO + 3O 



(2) 3CU + 30 = 3CuO 



(3) 3CUO + 6HNO3 = 3 Cu(N0 3 ) 2 + 3H.0 

 Adding up — 



3Cu + 8HNO3 = 3Cu(NO,) s + 2NO + 4H,0.' 



"What has the chemist to do with what ' is perhaps simplest to assume ' ? His 

 duty is to ascertain, as far as possible, what actually happens ; it is pretty certain 

 that the picture here painted for us is purely imaginary." 



So far the reviewer. I will now show that not one word of this criticism is 

 justified. 



The concluding paragraph of the section from which the above extract is taken 

 is as follows (p. 227) : 



"An alternative method is to represent the first stage of the reaction as 

 involving the liberation of hydrogen, which is then used up in reducing the nitric 

 acid to a lower stage of oxidation. It is sometimes assumed that this represents 

 the actual stages through which the reactions pass, but in reality they are probably 

 much more complicated. The remarkable fact that pure dilute nitric acid has 

 little or no action on copper or mercury unless a little nitrous acid is added cannot 

 easily be accounted for on this view as to the mode in which the reaction proceeds." 



The matter therefore stands thus : 



(1) The whole bearing of the section is misrepresented in the review. It is 

 evident from the parts quoted, especially the references to " an alternative method " 



69S 



