CASSELL'S CYCLOPAEDIA OF MECHANICS contains in a form convenient for ready reference and everyday use receipts, processes, and memoranda selected from a rich store of choice information contributed bv a staff of skilful and talented technicians, upon whose practical experience and expert knowledge the information is based. The matter contained in this volume has been carefully digested, freely illustrated, and made plain to those inexperienced.

All compilations of receipts and memoranda for the use of mechanics that have been published - and some have attained great popularity - differ from the present work in the important fact that every item in this volume is the paid contribution of an expert, written specially to satisfy the want of an inquirer, and each has challenged emendation from a wide circle of practical men. Corrective and supplementary matter supplied by these critical readers has been incorporated to ensure the greater efficiency of this work.

A superficial glance through the pages of this volume might tend to a false impression that the varied contents are not readily available for easy and systematic reference. However, this is not so. Experience has shown that it is not possible to classify paragraphs that often include matters essentially different so that there shall be a definite place for every item, and the impossibility of such a course is particularly emphasised in the present collection, which embraces subjects widely diversified. Even a little consideration of this Cyclopaedia would show that no possible arrangement of the paragraphs would place them so that the several facts contained in each could be found with ease and certainty. The copious index provides a means by which every separate particular and detail of any kind dealt with in the volume may be traced and referred to with the least amount of trouble. This index also brings together every reference to the same subject, however widely they may be scattered, and all varied notes included under one heading are properly analysed and, thus disclosed, regrouped with kindred topics.

No pains have been spared in the compilation of this index, which efficiently serves a purpose impossible to be met by any arrangement of paragraphs comprising the volume.

Amongst the items embodied in this work probably every reader can find some that contain information already known to him. . Possibly some readers may be able to supplement the particulars given in respect of matters with which they are familiar. Any authentic supplementary particulars that are likely to be of benefit and that would increase the usefulness of the information will be welcomed, and should be sent to the undersigned, with the view to including them in a second volume, now in preparation, that will be issued when ready.

Additional information or instruction on special details of the matters dealt with in Cassell's Cyclopaedia of Mechanics may be obtained by addressing a question to Work or Building World, from the contents of which journals this Cyclopaedia has been compiled, so that it may be submitted to the staff of contributors and answered in the columns of one of those journals in the usual course.

P. N. HASLUCK

La Belle Sauvage, London.

September, 1900.