NATURE 
27. 
DHURSDAY , MARCHE 145 ‘1912. 
HEAT ENGINE LABORATORY PRACTICE. 
The Testing of Motive-Power Engines, including 
Steam Engines and Turbines, Locomotives, 
Boilers, Condensers, Internal Combustion 
Engines, Gas Producers, Refrigerators, Air 
Compressors, Fans, Pumps, =c. By R. Royds. 
Pp. xii+396. (London: Longmans, Green, 
and Co., 1911.) Price gs. net. 
URING the last decade the 
engineering students has undergone a great 
change. 
engineering laboratory is not only a place where 
the student may see various principles previously 
expounded in the lecture-room put into practice and 
experimentally proved, but that it is a place where 
tests and trials are carried out upon a commercial 
basis and in an up-to-date manner by the student 
himself. If the student be put in direct charge of 
such tests, he will most assuredly develop that 
faculty of self-reliance which is one of the charac- 
teristics of a successful engineer. Side by side 
with this internal development there has been a 
vast change in the design and nature of motive- 
power engines, so that the modern laboratory has 
developed into an assembly of many varied types 
of prime movers. In acquiring information which 
will enable him successfully to cope with the dif- 
ferent practical difficulties met with amongst so 
many types, the student had to refer to many 
sources, the chief being the recent publications of 
the technical societies and Press. This book does 
that for them, and does it very thoroughly. It 
meets a distinct want, and at such a reasonable 
price it should be recommended to all college 
students. 
After giving it a welcome, we hope the author 
will not take it amiss if we indulge in complaint. 
Chapter i. treats of general principles of thermo- 
dynamics, units, and cycles of operation. On p. 6 
the author states that the centigrade scale of tem- 
perature measurement is used by some engineers, 
but more often by physicists and chemists. We 
believe we should be correct in saying all men of 
science save some, mostly engineers, use the centi- 
grade scale. Why do not engineers come into 
line? If the author would have braveiy adopted 
Cent. instead of Fahrenheit, he would have aided 
in bringing about a change which is slowly coming 
to pass. This leads us to suggest he might have 
included the pound-calorie in his enumeration of 
units of heat, a unit recognised by the University 
of London in their engineering examinations. 
Surely also it is more reasonable to expect the 
conversion of Fah. to Cent. readings to be made 
NO. 2211, VOL. 89] 
training of 
Our collegds"have recognised that the | 
by subtracting 32, then multiply by 5, than to 
| remember the suggestion on p. 6, for which no 
| reason is given. At the end of the book there is 
a series of tables, including conversion constants, 
properties of various vapours, and steam tables. 
We note that the latter are from “Marks and 
Davis.” We were hoping that when the last 
edition of Prof. Ewing’s book, “The Steam 
Engine,” was produced, the researches of Prof. 
Callendar were going to be recognised by English 
engineers. In an appendix to his book Prof. 
Ewing gives some properties of steam, and tables, 
which are certainly more rational in form 
than any others compiled from data outside Prof. 
| Callendar’s papers. We hope that in his next 
edition the author will introduce the pound-calorie 
unit and a short explanation of Callendar’s work 
in his chapter i., together with steam tables com- 
piled therefrom, and thus associate himself with 
Prof. Ewing and Dr. Mollier in bringing about a 
desirable change. The explanations of the various 
cycles of operations of the working fluid are well 
given, and in conjunction with lectures will make 
an excellent combination for the earnest student. 
The testing for accuracy of instruments such as 
gauges, indicators, &c., makes a long chapter for 
No. ii. This is good, as many are unduly pre- 
disposed to accept such as correct instead of 
always regarding them with suspicion. We should 
like to see a device for testing indicator springs 
hot, the methods shown being all under conditions 
dissimilar to their actual working state. Does the 
author use an indicator cock and connect an in- 
dicator to a dead-weight gauge tester, as shown 
in Fig 34? The fluid pressure will more nearly 
reproduce actual working conditions. Carefully 
and well written as chapter il. is, the author is best 
in chapter iii., on measurement of brake horse- 
| power. We are glad to see a description of a 
band brake which will give torque without causing 
a bending action due to large brake loads on one 
| side. 
| Chapter iv. is outside the scope of English 
laboratory work. The testing of locomotives is in 
the hands of a few, and those highly skilled, and 
| therefore needs not a general treatment as is here 
given, but a special treatise. Is it too much to 
hope that soon we may have in such a city as 
London an experimental plant for locomotive test- 
ing? It would surely prove of great use even 
if only for training up stokers at short notice. 
Chapters v., vi., and vii. are concerned with the 
testing of steam engines, turbines, and boilers. 
We are glad to see so much of the report of the 
Institution of Civil Engineers, vol. cl., embodied 
in these chapters. The author deals carefully with 
the “missing quantity” of steam as passed by the 
Cc 
