868 



SCIENCE 



[N. S. Vol. XXXVI. No. 938 



The first chapters explain the principle of 

 operation of the gas engine, and describe in 

 detail the various constructions that are em- 

 ployed in the engines on the market. The re- 

 mainder of the book is given up to practical 

 explanations of the setting up of a new engine, 

 the economical operation of engines, engine 

 care and maintenance, and explanations of 

 the troubles to which engines are subject, to- 

 gether with their remedy and prevention. 

 The book is written with the greatest possible 

 simplicity of expression. The illustrations are 

 especially prepared line drawings made by the 

 author, each one specifically illustrating some 

 particular point of construction." 



The book is well written and admirably cov- 

 ers the ground claimed for it, though at times 

 at the expense of scientific accuracy. It 

 should not only prove an excellent guide to 

 the amateur and the operator of small sta- 

 tionary plants, but it will be found extremely 

 useful to those more scientifically inclined, as 

 it supplies numerous details of construction 

 and methods of operation that can not be given 

 space in a scientific work, such as the details 

 of carbureters, ignition systems and spark 

 plugs. 



In attempting to explain electrical and 

 thermodynamic phenomena, the author at 

 times uses illustrations that would not stand 

 the test of scientific accuracy and that would 

 be misleading to those who had no further 

 knowledge of the subject. In the first chapter 

 he repeatedly speaks of converting water into 

 a gas and gasoline into a vapor. If the term 

 " vapor " coiild be understood by the reader in 

 one case there should be no diiEculty about it 

 in the other. In comparing the relative effi- 

 ciency of gas and steam engines, he states on 

 page 6 that : " When a fire is built under a 

 boiler only a small part of the heat is actually 

 applied to heating the water, for most of it 

 passes up the chimney or is otherwise wasted." 

 The author evidently confuses the chimney 

 wastes with the exhaust wastes. Boiler effi- 

 ciencies of 70 per cent, are not uncommon. 



On page 10, the statement, " The compres- 

 sion of the charge turns any liquid gasoline to 

 vapor " might be open to question. 



The most serious misconception that the 

 reader might gain is that electricity is a sub- 

 stance like water or air and that there is an 

 unlimited store of electricity in all substances 

 which only has to be set in motion to do work. 

 This is certainly contrary to the ordinary con- 

 ception of electrical energy and could only be 

 defended by resorting to the electron theory, 

 which would be beyond the scope of the work. 

 The author regards a dynamo as a machine 

 for setting electricity in motion. 



In describing the principle of action of the 

 Bosch high-tension magneto, when the cur- 

 rent in the primary coil is broken, the author 

 states, on page 145, that " The sudden rush of 

 intense primary current into the secondary 

 winding raises sufficient pressure to enable 

 the current to jump across the spark plug 

 gap," ignoring the real cause for the induced 

 current in the secondary. This action was 

 probably inferred because the diagram shows 

 the secondary winding to be in series with 

 the primary, for in describing other types, 

 where the windlings are separated, he cor- 

 rectly assumes the high-tension current in the 

 secondary to be caused by the rapidly dying 

 magnetism or change of magnetic flux in the 

 iron core. 



C. E. Jones 



West Virginia University 



SCIENTIFIC JOURNALS AND AUTICLES 



The closing (October) number of volume 

 13 of the Transactions of the American 

 Mathematical Society contains the following 

 papers : 



W. A. Hurwitz: "On the pseudo-resolvent to 

 the kernel of an integral equation." 



G. A. Miller: "Infinite systems of indivisible 

 groups. ' ' 



J. K. Lamond: "Improper multiple integrals 

 over iterable fields." 



T. H. Gronwall: "On a theorem of Fej6r and 

 an analogon to Gibbs 's phenomenon. ' ' 



W. H. Roever : ' ' The southerly and easterly 

 deviations of falling bodies for an unsymmetrie 

 gravitational field of force. ' ' 



Dunham Jackson : ' ' On approximation by trig- 

 onometric sums and polynomials. ' ' 



