Notices of Books . 
543 
1877.] 
pleasure and instruction we have derived from the perusal of his 
book, expressing our conviction that most of his readers will 
have occasion to pay him a similar tribute. 
The Amateur Mechanics' Practical Handbook. By Arthur H. 
G. Hobson. London : Longmans and Co. 
This little manual treats, in successive chapters, on the lathe 
and its uses ; on the drilling and planing machine ; on the vice, 
bench, and hand-tools ; on drawing and pattern-making; on the 
brass furnace and moulding ; on the construction of horizontal 
engines ; and on boilers. The author declares that his object 
has been to give plain, practical instructions, avoiding intricate 
subjects. Previous works which have dealt more or less promi- 
nently with this subject give, he finds, very vague instructions, 
or else are too theoretical to be of much use to the amateur — - 
charges which we think are not unfounded. The directions con- 
tained in this little volume are full and precise, and are illustrated 
with numerous figures. We believe that Mr. Hobson has, by 
the publication of this treatise, conferred a boon upon amateur 
mechanics — a somewhat numerous class. 
The Elements of Machine Design : an Introduction to the Princi- 
ples which Determine the Arrangement and Proportions of 
the Parts of Machines, and a Collection of Rules for Machine 
Design. By W. Cawthorne Unwin, Professor of Hydraulic 
and Mechanical Engineering at the Royal Indian Civil 
Engineering College. London : Longmans and Co. 
This work belongs to the series of “Text-Books of Science” 
issued by Messrs. Longmans, though by the strict methodologist 
it would be pronounced as belongingto the domain not of science , 
but of art — a distinction too commonly lost sight of, and, if we 
may judge from the last sentence of the Preface, not fully com- 
prehended by the author. 
In the first chapter Prof. Unwin treats of the materials used 
in the construction of machines. Here the properties of the 
various kinds of cast- and of wrought-iron are carefully ex- 
plained. Phosphor-bronze is noticed at some length, the author 
expressing the opinion that it is likely to be of great service in 
machine construction. Its chief drawback in the eyes of the 
chemist is that its manufacture withdraws a portion of phosphorus 
from natural circulation. Might not an alloy of similar proper- 
ties be obtained by substituting arsenic for phosphorus ? 
