442 



NA TURE 



[September 30, 1922 



use of red glass for obtaining approximately mono- 

 chromatic light. This is a factor of fundamental 

 importance when temperatures of the order of 3000° C. 

 have to be measured by means of pyrometers calibrated 

 on the basis of Wien's law to represent the distribution 

 . in the spectrum of a " full radiator." The 

 " disappearing filament " type of pyrometer has been 

 greatly developed in recent years at the N.P.L. and 

 elsewhere, and it would appear that, in time, it will 

 supplant most of the other types now in use for high- 

 temperature measurements. 



Thermometry is covered lay a comprehensive article 

 written by Mr. \V. F. Higgins. A detailed account is 

 given of the N.P.L. equipment for thermometer test- 

 in^, together with a complete discussion of the 

 mercurial thermometer. No consideration is given to 

 vapour-pressure thermometers. During the war many 

 thousands per week were made for use on aircraft, and 

 they are also being extensively fitted to motor-car 

 radiators at the present time. Doubtless the new 

 mercury-in-steel transmitting thermometers, which 

 have been successfully developed and are coming into 

 wide use, will receive a longer notice in a future 

 edition. 



Mr. G. S. Baker writes on ship resistance, Prof. 

 Horace Lamb contributes mathematical articles on 

 Fourier's series, etc.. Dr. A. W. Porter treats of thermal 

 conductivity, and Mr. Jakeman deals with the measure- 

 ment of pressure. 



We regret that we have not space to notice the 

 numerous short articles scattered throughout the 

 volume, some of which are intended to supplement 

 the longer articles. 



There is an excellent name-index. The references 

 are plentiful, and appear to have been carefully checked. 

 The only slip which we have noticed is on page 1025, 

 the Physical Society modestly confining itself to 

 Proceedings, not Transactions, as implied by the 

 writer. We notice that the names of Mr. Whetham 

 (Phase Rule) and Miss Austin (Units of Measurement) 

 have been omitted from the list of contributors on 

 p. vii. 



The printers have done their work well, and the 

 publishers are to be congratulated on their enterprise 

 and the general " turn-out " of the book. It was 

 inevitable that a book of 1000 or more pages of this 

 type should be expensive. The pity of it is that the 

 price will put it out of the reach of so many students. 

 It is true that they may have recourse to the nearest 

 library, but the book is such that one would like to see 

 every senior student of the subject with his own copy. 

 Some of the articles will be a revelation to him. bearing 

 as they do little resemblance in substance and treat- 

 ment to the majority of the present-day text-books. 

 NO. 2761, VOL. I 10] 



The division of the Dictionary into volumes on a 

 subject-basis, and the fact that individual volumes are 

 purchasable, are features greatly to be commended. 

 Perhaps in the future it may prove possible to extend 

 the system and divide the Dictionary into, say, double 

 the number of smaller volumes, each confined to one 

 main branch of the subject, and proportionately less 

 costly. The volumes would be lighter to handle, and 

 the formidable task of keeping so large a work abreast 

 of modern science would be much facilitated. 



G. W. C. Kave. 



Position of Agriculture in India. 



Agricultural Progress in Western India. By G. Keat- 

 inge. Pp. xii-t-253. (London: Longmans, Green 

 and Co., 1921.) 6s. net. 



AGRICULTURAL conditions in India are such 

 that any estimate of progress must be largely 

 indirect. The bulk of the land is farmed in small 

 holdings by peasants who keep no accounts, and sell 

 their surplus products in local markets which render 

 no statistical returns ; again, the value of export crops, 

 such as cotton, is subject to wide fluctuations owing to 

 the erratic rainfall. But, by a consideration of other 

 factors, such as the area under cultivation, changes 

 in land values and rentals, irrigation schemes, and 

 the standard of living, there is definite evidence of 

 progress. Mr. Keatinge has spent thirty years in the 

 midst of agricultural problems in the Bombay Presi- 

 dency, and in this very interesting book he sets out his 

 estimate of the progress that has been made, the 

 obstacles to further advancement, and a proposed 

 future policy. 



With regard to the obstacles in the way of further 

 advancement, the most serious one is the Hindu law 

 of inheritance, by which each male member of a 

 family is entitled to an equal share of the family 

 property. This results, not only in the division <>l 

 farms into uneconomic units, but in a further sub- 

 division into scattered plots — a process reminiscent 

 of the old three-field system in England. Another 

 fundamental difficulty is that cattle cannot be bred 

 and kept solely for profit, owing to their significance 

 in the Hindu religion. They are of inefficient types, 

 used of necessity in an uneconomic manner, and are 

 more of a hindrance than a help to the struggling 

 farmer. As an illustration of the difficulty of introduc- 

 ing improvements which do not clash seriously with the 

 social and religious habits of the cultivators, the author 

 considers the use of irrigation water. It appears that, 

 financially, most irrigation canals are unsuccessful 

 owing to the slow manner in which these facilities are 



