36 



THE AGRICULTURAL NEWS. 



February 10. 1917. 



A HANDBOOK FOR CANE-SUGAR MANUFAC- 

 TURERS AND THEIR CHEMISTS. By Guilford L. 

 Spencer, D.Sc. John Wiley and Sons New Yotk; Chapman 

 and Hall, London. -Jth Edition. Price 15.s. net. 



This handbook is so well known as to need no introduc- 

 tion, but the appearance of a new edition affords welcome 

 opportunity for calling attention to it. A feature of the 

 present edition is the increased jonsideration given to matters 

 relating to the actual manufacturing processes, in addition to 

 matters pertaining to the chemical work involved in the 

 guidance of these proce.sses. 



The position and experience of the writer as Chief 

 Chemist in Charge of Manufacture of the Cuban American 

 Sugar Company enable him to write with unrivalled authority, 

 the information that is given being the result of long, practical 

 acquaintance with all that pertains to the manufacture of 

 sufar and the chemical work connected therewith. 



The first part of the book deals with processes of manu- 

 facture and the machinery incidental thereto: this part of 

 the subject has been treated with considerably greater detail 

 than in former editions, a point which will be appreciated 

 by those having charge of sugar factories in view of the 

 advances that have been made in recent years. 



In brief but instructive outline, consideration is given 

 to the sugar-cane and its composition as being the raw 

 material of the industry; then follows an account of the mills, 

 engines and boilers, the various forms of clarifiers and 

 defecators and their mode of use. In this section useful infor- 

 mation is given concerning the manufacture of plantation 

 white sugar, a subject of pressing interest to sugar factory 

 managers at the present moment: indications are given of the 

 principal processes in u.se in various parts of the world; 

 these include reference to sulphitation i)rocesses as well as to 

 single and double carbonation and use of Norit. The methods 

 of working these various processes are outlined together with 

 the manner of making the various tests nece.ssary for their 

 successful operation. 



A useful section deds with matters pertaining to the filtra- 

 tion of juice and filter pres.ses and with the chemical reagents 

 used in purifying the juice, interesting information drawn 

 from practical experience being given. 



The section dealing with the vacuum pan and the 

 methods of crystallizing the sugar is calculated to be of great 

 service to factory managers, useful process of sugar boiling, 

 based on modern practice, are given; from the writer's 

 exceptional connexion with the sugar industry on a large 

 scale the information here given will command close atten- 

 tion on the part of practical men, as will his remarks about 

 curing and storing the sugar. 



The first part of the work closes with a useful 

 account of the work of sugar refining and the processes 

 incidental thereto. 



r.everting to his earlier edition of this book it may 

 perhaps be stated that managers and chemists would be 



grateful to Dr. Spencer if in a future edition he enlarged 

 the section on fuel and were to describe m ore fully the 

 methods of analysis of furnace gases and the manner of using 

 the information obtained therefrom for the economical use 

 of fuel. With increasing maceration and the use of steam 

 for a variety of purposes the fuel question is likely to assume 

 increasing importance. 



Being largely written for chemists with a view to the 

 adequate application of chemical knowledge to the direction 

 of the processes of -sugar manufacture, the second part of the 

 book is extremely full and complete. The sugar factory 

 chemist will here find an invaluable store of information in 

 the most compact form, compiled by a writer of unique 

 experience. 



The methods of controlling the work of modern sugar 

 factories in all the various stages of sugar making are given 

 in detail, these are invaluable to the factory manager and 

 chemist . 



In this section of the book the sugar chemist will find 

 full information to guide him in the conduct of his work 

 relating to sugar manufacture in all its branches together 

 with full information concerning the manner of examining 

 the various substances incidentally met with in sugar 

 making. 



The great progress that is being made in sugar manu- 

 facture calls for increasing accuracy in methods of chemical 

 investigation and control. The work of a well conducted 

 sugar laboratory calls for the employment of refined methods 

 of analysis coupled with close attention to such matters as 

 the effect of temperature on the results of the analytical 

 processes, and this in an unusual degree, seeing that so much 

 of the work is carried on in the tropics and that so many of 

 the analytical processes have a physical basis where temper- 

 ature changes exert marked inHuence. 



The chemical processes involved also require to be 

 carried out with a high degree of accuracy. 



In all that pertains to these matters the book contains 

 most valuable information. The appliances and reagents are 

 all carefully described and their uses indicated, the precautions 

 necessary for accurate working being explained. It is 

 impossible within the scope of a brief review to draw atten- 

 tion to many points of detail. 



The importance now attached to matters calculated to 

 ensure minute accuracy is vvell illustrated in this work by the 

 detailed attention given to such a subject as the effect on the 

 polarimeter reading of the volume of the lead precipitate 

 produced in the process of clarifying the sugar solution; at 

 one time chemists of repute questioned if there were any 

 effect, the extent of it is so small; now it is recognized as one 

 of the sources of error of analysis in cases where accurate 

 work is required. Other sources of minute error similarly 

 receive attention. In this connexion, perhaps, it may be 

 suggested that Dr. Spencer may look further into the question 

 of the possibility nf error being introduced by the precipitation 

 of levulose by basic lead acetate; his views on this point are 

 possibly not fully up to date 



A most valuable feature is the extensive .series of tables 

 which the book contains, these tables include those giving 

 the physical constants relating to the various substances of 

 importance in sugar work, the authority for each being given; 

 there are many useful tables for shortening the labour of 

 calculations in the work of analytical routine and many others. 

 Workers of experience know how frequently they require to 

 refer to some authority in regard to a point of physical or 

 chemical importance, and how useful and convenient it is to 

 have brought t'.j^cther such a collection of data of recognized 



