482 



NATURE 



[June 16, 192 1 



L-oncerned, we believe they are not satisfied with 

 import duties, and want prohibition of import 

 for a time, with permits to import in special 

 cases. Many consumers have stated their prefer- 

 ence for a system of subsidies to enable prices to 

 be low enough to compete with foreign goods. 

 Such a scheme naturally offers difficulties, and 

 there would need to be assurance that efforts at 

 improvement are being made. There seems to 

 be no reasonable objection to the price being 

 made as nearly as possible equal to that of the 

 foreign article, so that the competition should 

 become one of quality. The Bill, however, will 

 probably be passed, although it may still be pos- 

 sible to insert provisions to enable free import to 

 recognised scientific institutions. Such permits 

 must be of a general character, not requiring re- 

 newal, and not demanding the intervention of the 

 Customs or other Government Department. No 

 special licences for individual cases would be 

 satisfactory. 



How obstructive to scientific progress the 

 Customs regulations may be is shown by letters 

 that have appeared in these columns. The ques- 

 tion of books is a very serious one. Incidentally, 

 reference may be made to the increasing difficulty 

 of publication of scientific papers, which seems 

 to be greater in England than in other countries. 

 But here again what is wanted is a general fall 

 in prices, and this can be brought about only by 

 a return to normal trade relations throughout the 

 world. 



Much stress was laid by certain speakers in the 

 House of Commons on the necessity of our indus- 

 tries as a national insurance in case of future 

 war. The only remark that need be made in this 

 place is that the most important matter is to 

 keep abreast of scientific work in other countries. 

 Restriction of research is likely to do more harm 

 than the more or less ineffective artificial protec- 

 tion of a few industries would do good. It is to 

 be hoped, therefore, that institutions in which 

 such scientific research is carried on will be placed 

 beyond the effect of the new restrictions on 

 import. 



Steam and Thermodynamic Theory. 



Properties of Steam and Thermodynamic Theory 

 of Turbines. By Prof. H. L. Callendar. Pp. 

 ^i + 53i- (London: Edward Arnold, 1920.) 

 40S. net. 



IN this substantial volume Prof. Callendar has 

 set his seal to the experimental and theoreti- 

 cal investigations of the properties of steam on 

 NO. 2694, VOL. 107] 



which he has been engaged for many years. By 

 these investigations, which have done much to 

 advance technical thermodynamics. Prof. Callen- 

 dar has made the engineering world his debtor. 

 It is twenty-one years since he first pub- 

 lished, in the Proceedings of the Royal Society 

 for June, 1900, his paper on " the thermo- 

 dynamical properties of gases and vapours as 

 deduced from a modified form of the Joule-Thom- 

 son equation, with special reference to the proper- 

 ties of steam." 



With the publication of the book now under 

 review Prof. Callendar 's theory comes of age. 

 The book leads up to, and includes, his steam 

 tables, which were issued separately five or six 

 years ago and are accepted as the standard 

 tables, at least by English engineers. Here the 

 author describes, much more fully than before, 

 the basis of the tabular work, discusses its agree- 

 ment with the latest results of observation, and 

 replies to objections that have been taken to his 

 method on the part of some American writers. 

 Into this controversial matter there is no need to 

 enter here : the replies will have answered their 

 purpose if they succeed in removing misconcep- 

 tions regarding the scope and character of Prof. 

 Callendar's fundamental work, which, indeed, his 

 own earlier papers can scarcely be said to have 

 presented in a form that made its meaning very 

 clear or its importance obvious. 



Perhaps for that reason engineers were slow 

 to appreciate the practical bearing of Prof. Callen- 

 dar's treatment of the properties of steam. The 

 first of them to do so was Prof. Mollier, of Dres- 

 den, himself distinguished for original contribu- 

 tions to technical thermodynamics, who in 1906 

 published a set of tables and diagrams for steam 

 based on the Callendar characteristic equation. 

 Shortly afterwards the methods of Prof. Callendar 

 and the tables and diagrams of Prof. Mollier 

 were brought to the notice of English engineers 

 by the present writer in the third edition of his 

 book on "The Steam-Engine and other Heat- 

 Engines." 



Prof. Callendar's own tables, published in 1915, 

 embody the results of a more complete application 

 of his methods, and make use, in some particu- 

 lars, of later data. They give all the necessary 

 figures for properties of steam throughout the 

 range of temperature and pressure which is usual 

 in the practice of steam engineering. It is the 

 essence of Prof. Callendar's method to secure 

 results which will be thermodynamically consistent 

 with one another, and will also agree with the 

 results of experiment within a limited but suffi- 

 cient range. His characteristic equation makes 

 no pretension to be applicable outside that range. 



