Practical Pattern Making. F. W. Barroows. 326 pp. 7x5 in. 148 Illustrations. Cloth. Price $2.00, The Norman W. Henley Pub. Co., New York. It requires the reading of but a few pages to disclose the fact that the writer is a practical mechanic, is well posted as to the best methods of using the tools and materials for pattern making, and knows what is good practice in design and construction. The occasional sarcastic flings at other equally competent workers and writers in this field is rather likely to give the reader an unfavorable impression of what is really an excellent book. The examples of different kinds of pattern work are well selected, the advantages of a given method of construction plainly stated, accompanied by considerable general information. A system for marking and recording patterns is given which would be of much value if adopted by shops having any considerable number of patterns to store, and which are liable to be wanted at frequent intervals.

Gas, Gasoline and Oil Engines, Including Producer Gas Plants. Gardner D. Hiscox, M. E. 442 pp. 9x5 1/2in. 351 Illustrations. Cloth. Price $2.50 net. The Norman W. Henley Pub. Co., New York. The rapid development of gas engines during the past few years has necessitated the re-writing of this book, of which this is the 15th edition. Being much enlarged, and the revision so comprehensive, required new plates, and the result reflects much credit upon both author and publisher. The engineer or operator, and especially the repair man, must of necessity be familiar with the design and construction of the leading types of engines, and unless exceptionally situated, would find it difficult to acquire this knowledge as easily as he can by a study of this book.

The general theory and design are comprehensively treated in the first eight chapters; the several parts are taken up in the following seven chapters; particular types, including automobile, measurement of power and testing take the next five chapters; marine and bicycle motors the two following; kerosene, oil and distallate motors follow, concluding with a lengthy chapter devoted to producer gas and its production. A list of patents granted since 1875, and the names os builders of all types in the United States and Canada complete the book, making it very comprehensive and of the greatest value to anyone desirous of taking up the study of internal combustion engines.

An Elementary Text Book of Theoretical Mechanics. George A. Merrill. B. S. 267 pp. 8x5 1/4 in. 168 Illustrations. Half leather. Price $1.50. American Book Co. New York.

The time is coming when Mechanics will not be taught in the upper classes as a part of the course in Physics, but as this will in many schools require a radical readjustment of the curricula, it will remain for those schools fortunate in having progressive directors to lead the way, prove the desirability of such separation of studies, and the advantages to the pupil. This book has been written in accord with this idea, and provides an excellent course for pupils of upper classes expecting to later take a technical college course. No knowledge of calculus is required. A sufficient number of examples are given to thoroughly illustrate each topic.

In 1867 John O'Reilly, a trader in South Africa, stopped for the night at the house of a farmer. He noticed that the farmer's children were playing with some pebbles they had found in the river. O'Reilly took one of the pebbles to Cape Town where an authority called it a diamond of 22 1/2 carets and paid him $3000 for the stone. The farmer at whose house O'Reilly stayed remembered that he had seen an enormous stone in the hands of a Kaffir witch doctor, and from the Kaffir he traded his entire live stock for the stone and a few days after sold it at Cape Town for $56,000. This diamond was afterwards known as the famous " Star of South Africa." It weighed 84 1/2 carets in the rough and was a stone of unsurpassed brilliancy. This was the beginning of the South African diamond mining, for less than a few months 15,000 persons were prospecting.

The total value of all diamous, mined and sold to date is placed by an authority at $1,100,000,000, and of this vast sum that one-third of the amount represents the purchases of citizens of the United States.