THE "WESTMINSTER" SERIES 



The Testing of Rubber Goods. Gutta-Percha. Balata. Biblio- 

 graphy. Index. 



Tells all about a material which has grown immensely in com- 

 mercial importance in recent years. It has been expressly written 

 for the general reader and for the technologist in other branches of 

 industry. 



Glass Manufacture. By WALTER ROSENHAIN, Superin- 

 tendent of the Department of Metallurgy in the National 

 Physical Laboratory, late Scientific Adviser in the Glass 

 Works of Messrs. Chance Bros, and Co. With Illustra- 

 tions. 



CONTENTS : Preface. Definitions. Physical and Chemical Qualities. 

 Mechanical, Thermal, and Electrical Properties. Transparency 

 and Colour. Raw materials of manufacture. Crucibles and 

 Furnaces for Fusion. Process of Fusion. Processes used in 

 Working of Glass. Bottle. Blown and Pressed. Rolled or 

 Plate. Sheet and Crown. Coloured. Optical Glass : Nature 

 and Properties, Manufacture. Miscellaneous Products. Ap- 

 pendix. Bibliography of Glass Manufacture. Index. 



This volume is for users of glass, and makes no claim to be an ade- 

 quate guide or help to those engaged in glass manufacture itself. For 

 this reason the account of manufacturing processes has been kept 

 as non-technical as. possible. In describing each process the object 

 in view has been to give an insight into the rationale of each step, so 

 far as it is known or understood, from the point of view of principles 

 and methods rather than as mere rule of thumb description of manu- 

 facturing manipulations. The processes described are, with the 

 exception of those described as obsolete, to the author's definite know- 

 ledge, in commercial use at the present time. 



Precious Stones. By W. GOODCHILD, M.B., B.Ch. With 

 42 lUustrations. With a Chapter on Artificial 

 Stones. By ROBERT DYKES. 



LIST OF CONTENTS : Introductory and Historical. Genesis of 

 Precious Stones. Physical Properties. The Cutting and Polish- 

 ing of Gems. Imitation Gems and the Artificial Production of 

 Precious Stones. The Diamond. Fluor Spar and the Forms of 

 Silica. Corundum, including Ruby and Sapphire. Spinel and 

 Chrysoberyl. The Carbonates and the Felspars. The Pyroxene 

 and Amphibole Groups. Beryl, Cordierite, Lapis Lazuli and the 

 Garnets. Olivine, Topaz, Tourmaline and other Silicates. Phos- 

 phates, Sulphates, and Carbon Compounds. 



An admirable guide to a fascinating subject. 



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