508 



THE INDIA RUBBER WORLD 



[May 



1920. 



however, presumably deterniiiuil uii tlie raw and vulcanized 

 rubbers at room temperatures, whereas Mr. Sanderson's measure- 

 ments of expansion have been taken at the temperature of vul- 

 canization. The difficultj- as regards the increased specilic grav- 

 ity of vulcanized rubber can probably be explained by assum- 

 ing that vulcanized rubber possesses a greater coefficient of tem- 

 perature expansion than raw rubber so that although a given 

 weight of vulcanized rubber may occupy a larger volume than 

 that of raw rubber at the vulcanizing temperature, it may occupy 

 a smaller volume at room temperature. 



I therefore suggest that, to make the matter clear, .Mr. San- 

 derson should amplify Conclusion 5, by stating definitely what 

 he means by the point of vulcanization ; and Conclusion 6 also 

 may require modification unless it can be shown that the spe- 

 cific gravity of vulcanized rubber is greater than that of raw- 

 rubber at the temperature at which vulcanization is taking place. 

 Henry P. Stevens. 



15 Boro', London Bridge, S. E. 1. 



SANDERSON'S REPLY. 



To THE Editor of The Indi.\ Rubber World : 



DEAR SIR— Dr. Stevens' points are well taken, but I be- 

 lieve his objections will be met if I make my meaning 

 clearer. 



(1.) The phrase, "point of vulcanization" was perhaps an 

 unfortiuiate expression to have used. I think every- 

 one will agree that vulcanization does take place grad- 

 ually and my experiments bear this out by showing 

 that there were no breaks in the cures. By "point of 

 vulcanization" I simply meant to describe that region 

 of vulcanization to which rubber is cured in ordinary 

 practice. 



(2.) In discussing the changes in specific gravity I simply 

 attempted to prove that the increase was due to the 

 external pressure which is applied during the cure. 

 I did this by comparing the results obtained under dif- 

 ferent degrees of external pressure. Samples cured 

 with low external pressure showed alinost no increase 

 in specific gravity, while those cured with high external 

 pressure showed considerable increase in specific 

 gravity. 



C. W. Sanderson. 



THE EDITOR'S BOOK TABLE. 



"A TABLE OF TENSILE STRENGTHS OF RUBBER. BY HENRY 

 W. Jacobsen and Joseph E. Partenheimer, 1919. Printed for the Fisk 

 Rubber Co., Chicopee Falls. Massachusetts. 



THIS publication consists of a series of tables arranged for as- 

 certaining the tensile strength of rublier test pieces. The in- 

 formation sought is tabulated under the dimensions of the cross- 

 section of the test piece arranged at the top of the table, with 

 observed pounds' pull registered at the breaking point recorded 

 at the side. This compilation will be found very convenient in 

 eliminating calculations in testing laboratories where the routine 

 calls for many tensile tests and quick information as to the 

 results. 



"THE METRIC FALLACY." BY FREDERICK A. HALSEY. THE 

 ."Vmerican Institute of Weiehts and Measures, New York, 1919. (Cloth, 

 octavo, 9M by 6 inches, 229 -1- 10 pages.) 



Mr. Halsey's plea against the general adoption of the metric 

 system appears, after fifteen years, in a second, revised edition, 

 brought up to date, several chapters by Samuel S. Dale having 

 been added. 



■aNORGANIC CHEMICAL SYNONYMS AND OTHER USEFUL 

 Chemical Data." By Elton R. Darling, New York. D. Van Nostrand, 

 1919. (Cloth, 4J4 by 7 inches. 100 pages.) 

 This book is the outcome of a series of articles dealing with 

 the subject which appeared in "The Chemical Engineer" in 1918. 

 It is prepared for the use of students, but will be found a con- 

 venience by the experienced chemist. About one-third of the 

 book is taken up by various useful tables of data concerning the 

 elements, specific gravity, temperature comparison, and standards 



uf weights and measures. Tlie remaining pages are devoted to 

 lists of chemical synonyms in chapters arranged alphabetically by 

 elements, each list being preceded by a brief account of the 

 element, in|luding its discovery and leading characteristics. 



The book concludes with a cross-index of chemical names as 

 an aid in finding true chemical names and other synonyms 

 associated with them. 



"INDUSTRIAL CHEMISTRY." A MANUAL FOR THE STUDENT 



and Manufacturer. Edited hv Allen Rogers. Third Edition, 1920. D. 

 Van Nostrand, New York. (Cloth, 6 by 9 inches, 1232 pages.) 



The third revised edition of this standard work on industrial 

 cheinistry appears after an interval of five years since the pub- 

 lication of the second edition. It has been enlarged by over 

 two hundred pages and seventy new cuts. 



The chapter on rubber has been enlarged by the inclusion of 

 new matter in nearly every section, although an exhaustive treat- 

 ment of the subject is not attempted. The chapter closes with 

 two pages of bibliography which includes references to certain 

 important legal decisions in causes relating to rubber-working 

 processes and products. The references to the literature of 

 rubber are extremely few. No mention is made, under periodi- 

 cal literature, of the leading rubber journals of America, Eng- 

 land, France, or Germany, all of which are important in the 

 industrial field. 



NEW TRADE PUBLICATIONS. 



GuTT.\ ri;uciiA & Rubber, Limited, Toronto, Canada, issued 

 its price list of "Maltese Cross" rubber footwear on March 1 

 for the season of 1920-21. Coincident therewith appeared an at- 

 tractive 64-page illustrated catalog numbered S'-24, showing the 

 company's latest styles in boots, lumbermen's arctics, excluders, 

 overs, slippers and footholds. It comprises a varied and in- 

 teresting line of attractive appearance and well-known quality. 



"The Thermoid News" is the title of a very neat semi- 

 monthly factory paper published by the Thermoid Rubber Co., 

 Trenton, New Jersey, for the benefit of its employes. It is full 

 of helpful hints, practical talks on trade topics, and entertaining 

 chats about the staflf and operatives in the big Trenton plant. 

 Chester A. Charles is editor, assisted by Fred Birkholtz, Harry 

 W. Searfoss. E. \\'. Craft. Richard A. Kirk and P. Krier. 



The Habirshaw Electric Cable Co., New York City, has is- 

 sued a 16-page illustrated pamphlet entitled "1650," outlining 

 succinctly and entertainingly the development of insulated wires 

 and cables from Guericke's first experiment in 1650 to the pres- 

 ent day. Incidentally some very interesting facts about the great 

 Habirshaw industry are presented, together with several views 

 about the firm's plant at Yonkers, New York. 



The Chicago Chemical Bulletin, published monthly by 

 the Chicago Section of the American Chemical Society, has 

 issued a pamphlet of 11 pages entitled "Chemists' First- .-Xid 

 Treatment", by Paul Nicholas Leech. The emergency treatment 

 of burns, abrasions, and bruises, and of internal conditions are 

 treated briefly but adequately. There are also addenda from the 

 "Handbook of Therapy" on poisons. 



The Motor & Accessory Manufacturers' Association issues 

 under the title, "The Triumph of Team-Work." a handsome 

 pamphlet containing letters from many firms, praising the work 

 of the association. 



L. E. Knott Apparatus Co., Boston, Massachusetts, in 

 their Catalog 24C present a valuable descriptive list of chemical 

 and biological apparatus, the former of which are of interest to 

 rubber chemists. 



The Buffalo Foundry & Machine Co.. Buffalo, New York, 

 has selected a landscape of unusual beauty and brilliancy of color, 

 Thomas Aloran's "Castle in Old Mexico, Built During the Days 

 of Maximilian." to decorate its calendar for 1920. The picture. 



