ToL. XII. No. 300. 



THE AGKICULTURAL NEWS, 



1)7 



^9r^. 



PLANTATWX WHITE SUGAR MANUFACTURE. 

 By \V. H. Th Harloff and H. Schmidt, translated from the 

 Dutch by J. J'. Ogilvie. Normaa R'idgtr. T.ondon, 1913. 

 Price, 7s. •!(/. 



Until quite recently the manufacture in the West 

 Indies of white sugar in plantation factories has not been 

 economically worth while owing to fiscal difficulties con- 

 nected with the United Stales tariff. Recent changes, 

 however, have altered the position in this respect, and it 

 will now be possible for central factories to consider seriously 

 the introduction of methods whereby the necessary purifica- 

 tion can be eflfected and the refined sugar placed direct upon 

 the retail market. The book under review has therefore 

 appeared at a very opportune moment. This circumstance, 

 taken together with the concise yet comprehensive nature of 

 .the carefully classified subject-matter, should ensure the 

 book a rapid sale. 



In the first section of the book dealing with the 

 chemistry of white sugar manufacture, the pages dealing 

 with colouring substances in sugar-cane are of particular 

 interest. It would seem that if white sugar manufacture is 

 taken up e.xtensively in this part of the world, the question 

 of colouring matter in sugar cane varieties will be a factor to 

 be taken into consideration in selection work. 



After describing the different forms of fermentation 

 that occur in sugar factories, the book deals next with 

 the manufacturing processes proper. Carbonic acid satu- 

 ration (cabonatation) is taken first. An interesting and 

 instructive historical account of the process is given, 

 together with details of its employment in beet sugar 

 factories. Some fourteen pages are devoted to double car- 

 bonatation, which is recommended for tropical factories, on 

 the score that it is much safer than single carbonatation 

 On the other hand, the single process is much quicker, and 

 the various advantages and disadvantages of the processes 

 are set out in detail on the pages which follow. Much useful 

 information is then presented concerning the .supply of 

 carbonic acid and its control. 



Before coming to the subject of raw juice .sulphitation, 

 an account is given of an intermediate or rather a modified 

 process of the Kuropean carbonic acid saturation, known as 

 the acid thin juice process. This consists in principle in 

 sulphuring carbonated juice with a view to the removal of 

 colour occasioned by the action of carbonates on glucose. 

 Although the acid thin juice process may be applied in double 

 a.s well as in single carbonatation, it appears to be especially 

 applicable to the latter. 



Raw juice sulphitation, which next receives attention in 

 the book, is employed much more frequently than is carbona- 

 ■tation. Chemically, the two processes are of a parallel 

 Tiature and the study of one assists in obtaining 

 an intelligent understanding of the other. Where cane 

 varieties under cultivation are not highly coloured, sulphita- 

 tion appears to be the more satisfactory process to employ, 



although it has to be remembered that difficulties in regard 

 to filtration constitute a serious objection to the employment 

 of sulphitation. 



In the pages which follow, the methods of operating the 

 process, and the treatment of thick juice are carefully 

 expounded. A final chapter is added on the subject of curing. 



PRACTICAL AGRICULTURAL CHEMISTRY. 

 By S. .1. M. Auld, D.Sc, Ph. D, F.I.C, F.C.S., and D R. 

 Kdwardes-Ker, B A , B.Sc. John Murray, London, 1913. 

 Price 5.S. net. 



Hitherto there has been no book published in England, 

 one might almost say in English, quite like the work under 

 review. It is essentially a laboratory book, yet by no means 

 merely a guide to analysis. It is an educational book, specially 

 adapted, we are told in the Preface, for candidates preparing 

 for the University of London B.Sc. degree in agriculture. To 

 avoid an entire lack of continuity, the authors have constructed 

 a comprehensive and detailed system of classification, but what 

 is still more important, have introduced before each impor- 

 tant practical process, a theoretical account of the point at 

 issue. This greatly enhances the educational value of the 

 book, inasmuch as the student of agricultural chemistry is 

 often at a loss to see exactly where his theoretical teach- 

 ings fall into line with his practical work. This difficulty 

 the book succeeds in overcoming, to a very large extent. 



The first section of the book concerns the chemistry 

 of plant life and includes the detection and deter- 

 mination of the ultimate and proximate constituents of 

 plants. Chapter III of this section is very interesting, 

 and treats of the groups known as alkaloids, glucosides, 

 organic acids, essential oils, tannins, reaios and the like, in 

 a new and instructive manner. Section II deals with the 

 soil in its various chemical and physical aspects. In view 

 of their great bio-chemical importance, it is satisfactory to 

 note that bacteria are brought within the student's range 

 experimentally. In the third section, methods of analy.sing 

 the various manures are given and a special chapter is 

 devoted to mixed manures. Feeding stuffs receive attention 

 next — first concentrated foodstuffs like oil cakes, and then 

 succulent food, such as 'roots', green fodder, etc. Special 

 attention is given to secondary feeding stuffs — molasses, 

 spices and the like. 



The last two sections are devoted ]to dairy products and 

 the examination of waters and soaps. 



In general, the employment of this volume in the 

 Tropics can be recommended, since most of the determinatioas 

 in regard to soils, fertilizers and dairy produce hold good 

 irrespective of local environment. The information, however, 

 in regard to sugar is not sufficiently complete for the require- 

 ments of students in cane growing countries, though it will no 

 doubt be found sufficient to meet the demands of th° English 

 student. In the Tropics, reference at least to Clerget s method 

 would be desirable. 



One or two points of practical importance in the book 

 appear to be open to criticism, for instance the method givea 

 on page 48 in regard to the preparation of calcium citrate, 

 and that concerning ash determination in molasses presented 

 on page 172 



On the whole, however, very few faults can be found 

 with the book, which is comprehensive, original and particu- 

 larly well illustrated — a feature of no little importiince in 

 a practical manual. 



We are sorry that in the Preface we are unable to 

 join with the authors in regard to an expression of thank.s 

 to the compiler of the index — a feature of the book which 

 appears to us to be distinctly inadequate. 



