This book consists of a reprint of the third edition of my Methods of Glass-blowing, together with a new chapter in which I have described the comparatively new art of working vitreous silica.

            The individual operations of glass-blowing are much less difficult than is usually supposed, and considerable success in the performance of most of them may be attained by any one who is endowed with average powers of manipulation and who is moderately persistent. Constructing finished apparatus is often more difficult, as it may involve the performance of several operations under disadvantageous conditions, and may demand a little ingenuity on the part of the operator. But I think the suggestions in Chapter IV. will make this comparatively easy also to those who have mastered the operations described in Chapter III.

            The working of vitreous silica, though more tedious and expensive than glass-blowing, is not really more difficult, and as it seems certain that this new material will soon play a useful part in chemical and physical research, I believe the addition now made to the earlier book will add considerably to its value.

            As glass is much less expensive to work with than silica, the beginner will find it best to spend a few days working with the common gas blow-pipe and glass before he attempts to manipulate the new and more refractory material. Therefore, in writing the new chapter, I have assumed that the reader is already more or less familiar with the rest of the book, and have given only such instructions and advice as will be required by one who is already able to carry out simple work at the blow-pipe.

            W. A. SHENSTONE.

            Clifton College,
 Dec. 1901.