438 



NATURE 



[JUxNE 3, 1920 



biased scientific basis. Dr. Coffin, to bring out the 

 importance of the air-temperature correction, assumes 

 two cases, both with identically perfect barographs, 

 with no instrumental errors, one ascent in summer 

 and the other in winter to an altitude that both read 

 8 in. of mercury as the minimum pressure. He 

 assumes that in the summer case the average tem- 

 perature of the air is 10° C, and in the winter 

 -30° C, which values correspond closely to actually 

 observed figures. The true altitudes of these are 

 33»475 ft. (10,203 m.) for the summer instance and 

 30,929 ft. (9427 m.) for the winter, although the alti- 

 tude uncorrected for air temperature is 36,020 ft. 

 (10,979 m.) for both. Dr. Coffin states that the flight 

 made by Roland Rohlfs, the test pilot of the Curtiss 

 Engineering Corporation, on September 18, 1919, 

 attained an altitude of 34,910 ft. (10,640 m.), partially 

 corrected, but uncorrected for the average temperature 

 of the air column; the true altitude was 32,450 ft. 

 (9890 m.) corrected for air temperature. The altitude 

 attained by Major Schroeder, similarly corrected for 

 temperature, is 30,751 ft. (9373 m.). 



In Science of April 30, Prof. McAdie gives as ap- 

 proximate values, corrected for mean air column tem- 

 perature, vapour pressure, gravity, altitude, and lati- 

 tude : Rohlfs, 32,418 ft. (0880-5 "I-), and Schroeder, 

 31,184 ft. (9505 m..). 



The Meteorological Magazine for March, in an 

 article "The Highest Aeroplane Ascent," mentions 

 Major Schroeder's ascent on February 27 last 

 referred to above, and expresses the hope that 

 it will be authenticated in due course. The record 

 of person and Siiring, who, it is stated, reached 

 ';5,40o ft. (10,789 m.) in a balloon on July 31, 1901, 

 is mentioned as being generallv accepted as the 

 greatest height hitherto attained by aeronauts. The 

 article seems to throw some doubt on the lowest tem- 

 perature observed in the ascent by Glaisher and 

 Coxwell. 



Physical Problfems in Soil Cultivation.^ 



UP to the outbreak of the war the farmer could 

 generally rely upon an adequate supply of cheap 

 labour. He had no great necessity to introduce 

 labour-saving machinery into the routine of the farm. 

 But the increasing demands of the Army for men 

 and the menace of the submarine campaign brought 

 him face to face with the difficult problem of growing 

 more food with a greatly reduced staff". In such 

 conditions the employment of machinery was the only 

 solution, and although at the time it was introduced 

 mainly as a temporary measure, it is now quite 

 evident that economic conditions will cause it to be 

 retained permanently. During the war the rate of 

 progress in the industry of agriculture was necessarily 

 forced above the normal, and the urgent need at the 

 present time is to take stock of the position, so that 

 future developments may be guided along the right 

 lines. In this connection the report of the Depart- 

 mental Committee of the Ministry of Agriculture 

 on Agricultural Machinery appears at an opportune 

 moment. The report deals with " the further steps 

 which should be taken to promote the development 

 of agricultural machinery," and, so far as tillage 

 implements are concerned, falls naturally into two 

 sections, dealing with (i) fundamental research on 

 the physical properties of soil as affected by cultiva- 

 tion operations, and (2) the application of the know- 

 ledge thus gained to the design of new implements 

 and the improvement of old ones. 



1 Report of the Departmental Commit'ee of the Ministry of Agriculture 

 on Agricultural Machinery. (H.M. Stationery Office.) Price is. ntt. 



NO. 2640, VOL. 105] 



Taking the second section first, the Committee lays 

 great stress on the fact that all development in the 

 design of machinery has proceeded on empirical lines. 

 "Although searching questions were addressed to 

 several witnesses, we could not discover that any 

 real attempt had been made in the past to determine 

 the principles which underlie the design of the variety 

 of implements in use in modern farming." As a 

 result an enormous number of patterns of the same 

 implement are made, one manufacturer alone having 

 more than two hundred and fifty patterns of plough. 

 The Committee considers that much of this overlapping 

 and wasted effort will be avoided when the Ministry 

 of Agriculture sets up its projected Research Insti- 

 tute in Agricultural Machinery. 



The first section — research into the physical pro- 

 perties of soil — is regarded, rightly, as of priniary 

 importance. "Progress in research as regards tillage 

 implements must depend largely upon the results of 

 investigations into soil physics and the problem 

 of tilth." It is clearly pointed out that this research 

 must not be pursued with the immediate object of 

 obtaining "practical " results. A sound theory of 

 the interesting but complicated physical phenomena 

 shown by soil must first be built up. Once this is 

 achieved, the practical deductions will follow almost 

 automatically. The very nature of this work precludes 

 the possibility of forcing the pace, but it is suggested 

 that, as the work has been in progress for some time 

 at Rothamsted, it should be further developed by the 

 appointment of additional scientific assistants. 



If this were done it would be possible to pay more 

 attention to those physical problems concerned with 

 the soil tilth than is practicable at present. Tilth is 

 related to the production of compound particles or 

 aggregates in the soil, and to the factors causing 

 plasticity, cohesion, etc. At the same time a study 

 of the mechanical action of the plough could be 

 started having as its aim the specification of the 

 design of mould-board to meet different soil condi- 

 tions. This is an unsurveyed field and full of 

 promise. 



The report also deals with the educational and 

 research work which should be carried out at the pro- 

 jected Research Institute in Agricultural Machinerv. 

 especially from the engineering point of view. It 

 also advocates the appointment of an Advisory Com- 

 mittee, composed of representatives from the research 

 institutions, implement-makers, and agriculturists, to 

 co-ordinate the whole of the work. 



In the present article attention has been confined 

 mainlv to the sections dealing with the physical ques- 

 tions involved. The report covers a much wider field. 

 It is closely reasoned and convincing, and can be 

 cordially recommended to all concerned in the industry 

 of agriculture. B. A. Keen. 



The Anomaly of the Nickel Iron Alloys : 

 Its Causes and its Applications. ^ 



THE lecturer began by a reference to the work of 

 John Hopkinson, and to his own early work on 

 the perfecting of standards of length. His first experi- 

 ments were on nickel, which had two great advantages 

 over brass for metrological work, viz. its srnaller co- 

 efficient of expansion and its greater freedom from cor- 

 rosion. He would probably not have looked further 

 but for the difficulty at the time of getting large bars 

 of the material free from flaws. In investigating the 



1 Abstract of the Fourth Guthrie Lecture delivered before the Phys'cal 

 Society on April 23 by Dr. C. E. Guillaume. 



