474 Notices respecting Neiv Books. 



sacrificed through the desire to compress it within limits that are 

 obviously too narrow. 



Probably the first point that will strike the attention of every 

 reader of this work, is the fact that the scale of atomic weights 

 adopted in it is the so-called "unitary" scale proposed twenty 

 years ago by Gerhardt. It is an important indication of the direc- 

 tion in which chemical opinion has been moving of late years, that 

 Mr. Watts — a chemist of far too much experience and too sound 



judgment to have been influenced by the mere charms of novelty 



should have found it desirable to adopt Gerhardt's notation, and the 

 general system of ideas of which that notation is the exponent, in a 

 work which is in no way designed to advocate any particular set of 

 theoretical views, but simply to set forth in as clear and direct a 

 manner as possible the results of chemical investigation. Whatever 

 objections some chemists may still urge against this system, it is 

 a fact, which can no longer be overlooked, that the school by which 

 it has been adopted has acquired a degree of importance which 

 makes it necessary for every one engaged in chemical pursuits to be 

 acquainted with it ; and hence a work, such as the present, in which 

 this system is consistently carried out and applied to all chemical 

 compounds, acquires a value that is quite independent of any opinion 

 as to the truth or falsehood of the system itself. For the benefit, 

 however, of persons w r ho are likely to consult the Dictionary for 

 the sake of practical rather than of scientific information, the old 

 formulae, as well as the new, are given in all articles to which they 

 may be expected to refer. 



Although by far the greater portion of the two Parts now before us 

 is the work of Mr. W 7 atts himself, several very valuable articles have 

 been contributed by other writers, who seem to have well seconded 

 the editor in endeavouring to bring down to the most recent date 

 possible the information on the various subjects treated by them. 



One specially valuable characteristic of the work is the fulness 

 with which analytical processes of all kinds are described. Besides 

 an excellent series of articles devoted to the various branches of 

 analytical chemistry (Inorganic Analysis, by Mr. F. T. Conington ; 

 Organic Analysis, elementary and proximate, by the Editor ; Volu- 

 metric Analysis of Liquids and Solids, by Mr. Dittmar ; and Volu- 

 metric Analysis of Gases, by Dr. Russell), and those on Acidimetry, 

 Alkalimetry, and Alcohoiometry, all of which are very complete, we 



find under the heading of each of the more important substances 



such as Acetic Acid, Ammonia, Antimony, Arsenic — a detailed ac- 

 count of the processes to be adopted for its detection and quantitative 

 estimation. 



iter In a work of such magnitude, occasional errors in detail must be 

 looked for as a matter of course ; but almost all those that we have ob- 

 served are either obviously misprints, or have probably arisen from 

 the length of time which the work has necessarily occupied in going 

 through the press. To this latter cause is also doubtless due the 

 occasional omission of any mention of very recent discoveries. For 

 instance, in the article Alkali, we find nothing about csesium or 



