May 21, 189: 



NAIURE 



51 



The distinguishing feature of the book before us con- 

 sists in the use of the periodic arrangement as a means 

 of classifying the subject-matter of inorganic chemistry. 

 Here, the time-honoured methods of putting the facts 

 and theories of chemistry before the student are set aside, 

 and as the method adopted is novel to English text- \ 

 books, it may be advisable to consider its characteristics. 

 After a short historical introduction, the author pro- 

 ceeds to describe the occurrence, preparation, and 

 properties of the elements in the order in which they ' 

 are found in the periodic table. First, Group I., hydro- 

 gen and the alkali metals : then Group II., metals of the ' 

 alkaline earths, and so forth. The descriptions refer, as 

 far as possible, to the elements of the same group taken ' 

 collectively. 



The compounds of elements of the different groups 

 with the halogens form the next part, and in the intro- 

 ductory portion the student meets for the first time with 

 matter which it is customary to discuss at an earlier 

 stage in the text-books ; such matter as the distinction 

 between element and compound, the use of chemical 

 symbols, the gaseous laws, &c. The fourth part deals 

 with the oxides, sulphides, selenides, and tellurides, \ 

 and under these headings are to be found hydroxides, 

 hydrosulphides, &c., classed as compounds of the oxides 

 with water, hydrogen sulphide, &c. Here, also, are 

 treated the salts of the oxyacids, classed as double 

 oxides, and compounds as POCI3 treated as double ! 

 compounds with the halogens. 



Part V. gives an account of the borides, carbides, and 

 silicides ; such of the hydrocarbons as are considered, 

 and the organo-metallic compounds occur in this part. 

 Compounds with the elements of the nitrogen group, in- 

 cluding the cyanides, form Partvi. Alloys and amalgams 

 are discussed in Part vii. The first chapter of. the next 

 part gives a short account of spectrum analysis and the 

 rare earths. The second chapter is chiefly concerned 

 with the criteria for fixing atomic and molecular weights, 

 the Raoult methods finding a place, and the last chapter 

 is devoted to the periodic law. The closing part of the 

 book takes up, mainly with regard to the chemical prin- 

 ciples involved, the manufacturing processes usually 

 treated in the text-books. 



It will be seen, as the author states in his preface, that 

 the method adopted does away with the distinction 

 between metals and non-metals ; no special stress is laid 

 on the properties of acids as contrasted with bases ; equal 

 prominence is given to rare and more common substances ; 

 and the commercial importance of a substance or process 

 is not considered an argument for its special considera- 

 tion. 



Such a work as this may be looked at from two points of 

 view. Regarded as a systematic arrangement of the 

 facts of inorganic chemistry, from which any desired in- 

 formation may be speedily taken after one has become 

 familiarized with the method of classification adopted, 

 its success is undoubted. The book is quite in touch 

 with recent investigations, nothing of importance seems 

 to be omitted from the descriptive portion, and, what 

 is a recommendation to a large class of readers, the size 

 of the book is not excessive. Whatever be the results of the 

 system adopted, economy of space is assuredly achieved. 

 NO. 1 1 25, VOL. 44] 



To the teacher or to the advanced student who wishes 

 to use the book as a work of reference, or desires to 

 systematize his knowledge, it will be eminently useful. 



If, on the other hand, the system be regarded from 

 the point ot view of a basis for teaching, its construc- 

 tion from its very novelty must be open to discussion. 

 A method of teaching chemistry often employed may 

 be said to consist in giving the learner in as easy a manner 

 as possible the leading facts of chemical science with 

 regard, in the first instance, more to the correct apprecia- 

 tion of the meaning of the facts themselves, than of the 

 exact arrangement or classification of the same. To 

 this end the student is led from the study of the chemical 

 properties of commonly occurring bodies to the descrip- 

 tion of the elements contained in them, explanations of 

 chemical terms being given as they crop up, or in short 

 reviews at intervals not far apart. When the properties 

 of the elements are being explained, their reactions with 

 other elements have to be noticed, and hence it appears 

 natural to describe the important compounds of an 

 element after its own properties have been discussed. 

 The periodic system does not seem to provide the means 

 for such a course of teaching, and this appears to us 

 to be the main reason for its non-adoption in the text- 

 books. 



Indeed, the new method has little in common with 

 that indicated above. The entire series of the elements 

 apart from their compounds are described, and chemical 

 and physical terms are freely used without any attempt 

 being made to define them till all the elements have been 

 treated. In fact, a few terms, as critical point and heat 

 of formation, are used, but as far as we can see, not 

 defined in the book. Again, compounds containing a 

 common constituent are. classed together, but compounds 

 of what may be taken as a parent element are scattered 

 throughout the various groups. Surely, in connection 

 I with this point, reasons similar to those which lead to 

 I the grouping of compounds containing the same element, 

 I on the new system, would hold for the old method of 

 considering compounds. The position of the iron group 

 of elements after the aluminium group and of the copper 

 group — the last one described — may be taken as an indi- 

 cation that even in the author's opinion the periodic law 

 does not in all cases indicate most clearly the relation- 

 ships of the elements. Such considerations as these must 

 weigh with a teacher before he can adopt the system ; 

 during four years' experience, however, the author has 

 had no reason to doubt its success. 



The book is clearly printed, and the illustrations, though 

 not very numerous, are for the most part new. The 

 frequent use of vapour jackets in the apparatus repre- 

 sented is suggestive of the author's more recent contribu- 

 tions to scientific literature. The useful system adopted 

 by Ostwald in his " Lehrbuch," of indicating the state 

 of aggregation of a substance by the type, has been 

 employed. 



Setting aside the points which may be urged against 

 the work as a basis for teaching, the periodic law, as 

 expounded by Prof. Ramsay, does more than any other 

 system of classification to put the matter of inorganic 

 chemistry on a footing resembling that which holds for 

 organic chemistry. 



