290 



NATURE 



[May 6, 1920 



ing, and the argument is easily followed with the 

 aid of the many accompanying illustrations. 



Mr. Reid Moir's final chapter on " Pre-Palaeo- 

 lithic Man in England " is more discursive, and 

 suggests that we should turn to England rather 

 than to Asia for the earliest traces of man. The 

 detritus-bed at the base of the Pliocene Red Crag 

 near Ipswich is described as yielding rostro- 

 carinate and other worked flints. The age of the 

 Piltdown skull is also discussed, and it is regarded 

 as Pliocene. The conclusion is that English 

 " pre-palaeolithic " deposits should be more care- 

 fully studied than they have been hitherto, iand 

 the little book before us cannot fail to stimulate 

 such study. 



The Heat Treatment of Cast Iron, 



Malleable Cast Iron. By S. Jones Parsons. 

 Second edition, revised. Pp. xi+175. (London: 

 Constable and Co., Ltd., 1919.) Price 14s. net. 



THE first edition of Mr. Parsons's book on 

 malleable-iron founding was published in 

 1908. A second edition has now been issued. It 

 differs principally from the first in that it contains 

 two new chapters, one dealing with mixing by 

 analysis, the other with the measuriement of tem- 

 perature. There is also a brief addendum on 

 what is called "malleable cast steel." 



The high percentage of "waster " castings 

 formerly produced in malleable-iron foundries has 

 undoubtedly been reduced in the interval which 

 has elapsed between the appearance of the two 

 editions by adopting a more scientific method of 

 making up mixtures according to chemical 

 standards; but this alone is not sufficient to en- 

 sure a continuous output of good malleable cast- 

 ings. There has always been an undue amount 

 of wastage in the annealing process, chiefly owing 

 to irregularities in the temperature of the ovens. 

 This is inevitable when there is no means provided 

 for measuring the temperature. In the best 

 foundries the hopelessness of relying on the purely 

 human element has long been recognised, and it 

 has now been proved by the use of suitable pyro- 

 meters that a considerable saving in fuel may be 

 effected and the percentage of waster castings 

 due to imperfect annealing almost entirely elimin- 

 ated. The chapter on temperature measurement 

 gives a brief account of optical and thermo-couple 

 pyrometers and the methods of using them in this 

 industry. 



It is somewhat surprising that in a book which 



is evidently designed to assist the malleable-iron 



industry to more scientific methods of production 



there is no mention of the light thrown by the 



NO. 2636, VOL. 105] 



microscope on the structural changes which occur 

 in the malleablising process; nor is there any re- 

 ference to the mechanical properties of the various 

 types of iron produced. It is the microscope which 

 has shown what the essential difference is between 

 European malleable iron, which dates back to the 

 time of R6aumur, and the modern" Black Heart " 

 variety, which is an American product. This 

 instrument affords a valuable means of controlling 

 the extent of the malleablising action of the an- 

 nealing process. 



A valuable account of these two aspects of the 

 scientific control of malleable iron is to be found 

 in Dr. Hatfield's book " Cast Iron in the Light 

 of Recent Research." If a third edition of Mr. 

 Parsons's book is called for he would be well 

 advised to include a reference to these additional 

 methods of control. 



Our Bookshelf. 



The Running and Maintenance of the Marine 

 Diesel Engine. By John Lamb. Pp. xii-t-231-f 

 4 plates. (London : Charles Griffin and Co. , 

 Ltd., 1920.) Price 85. 6d. 

 This book opens with brief descriptions of 

 the properties of oil fuels, combustion, the modes 

 of working of four-cycle and two-cycle engines, 

 and the general arrangement of the marine Diesel 

 engine on board ship. The remainder of the book 

 is taken up with descriptions of details and the 

 manner in which these operate ; sections are in- 

 cluded dealing with high-speed Diesel engines for 

 driving dynamos and fans, steering-gears, running 

 troubles, and lists of stores which should be 

 carried. The book is profusely illustrated with 

 diagrams showing the construction of details ; as 

 the author's object has been merely to explain the 

 mode of working, many of these diagrams have 

 not been drawn to scale ; detailed descriptions of 

 parts which are common to all classes of engines, 

 e.g. connecting-rods and crank-shafts, are not in- 

 cluded. 



The book will appeal to and be found useful 

 by a large class of engineers whose experience has 

 been confined to the steam engine, both by reason 

 of the clearness of the matter included and by the 

 many useful hints which the author's four years' 

 sea-going experience in motor ships has enabled 

 him to give. For example : " In the same vessel 

 the scavenging valves would intermittently fail 

 to close, frequently to such an extent that the 

 escape valves on the scavenging air pipe would 

 lift. The scavenging pumps drew the air through 

 a ventilator passing up through the deck. It was 

 afterwards found that scale from the inside of the 

 ventilator was the cause of the valves failing to 

 close. The air was then taken from the engine- 

 room, when no further trouble was experienced." 

 Obviously hints of this kind are of .service not only 

 to the engineer on board ship, but also to the 



