January 2 2', 1920] 



NATURE 



543 



FormultB for Optical Glass," and a description of the 

 focimeter of the Royal Precision Laboratory, as well 

 as a selection of abstracts from foreign periodicals. 



In an article entitled "The ^ther versus Rela- 

 tivity " in the Januarv issue of the Fortnightly 

 Review Sir Oliver Lodge contends that as the current 

 ideas that the aether is an infinitelv extended uniform 

 medium as a whole at rest, and that absolute motion 

 is to be measured with respect to this ajther, are 

 simple and straightforward, they should be retained so 

 long as no clear proof that they are false is forthcoming. 

 The new theories express the facts of experience in 

 other terms, but they attribute the property of wave- 

 transmission to geometrical space free from any 

 medium, and are, in consequence, repugnant to those 

 ' with a competent faculty for rational philosophis- 

 ing." Sir Oliver Lodge urges the desirabilitv of com- 

 paring the speeds of light along and against a strong 

 magnetic field as a promising means of determining' 

 the density of the sether. Such a result would entirely 

 discredit the theory of relativity as a statement of real 

 fact. 



.A REPORT on the general theory of blade-screws, 

 forming Report No. 9 of the .American National 

 Advisory Committee for .Aeronautics, has been drawn 

 up by .Mr. George de Bothezat, of Dayton, Ohio 

 (Washington : Government Printing Office, iqiq). In 

 a problem like the present, in which the conditions 

 are far too complex to admit of an exact hvdro- 

 dynamical solution, any theory necessarily involves 

 assumptions which at best are only approximate. The 

 author applies elemental methods, first, to the slip 

 stream, and, secondly, to the region surrounding a 

 blade element, and, in common with many previous 

 investigations, neglect of the effects of radial motion 

 is one of the assumptions made in a first approxima- 

 tion. The theory appears to constitute an advance on 

 previous investigations, especially in the matter of a 

 detailed examination of the elements of fluid, and the 

 author is very careful in stating the assumptions on 

 which the work is based, and the justification for 

 which will necessarily depend on comparison of the 

 results with those of experiment. .An appendix deals 

 with the geometry of screw-blade drawing. The 

 method appears to neglect compressibility, and will 

 therefore bo applicable to air-screws of which the tip 

 velocity does not come too near the velocity of .sound. 



-An important paper on radio-transmission ami recep- 

 tion by Mr. J. H. Dellinger has been published by 

 the Bureau of Standards, Washington. The difficulty 

 experienced by practically every man of science in 

 understanding the ordinary radio theory is in master- 

 ing the proof of the formula which gives the magnetic 

 force at a distance from the sending antenna in terms 

 of the wave-length of the radiation. He objects to 

 accepting it without proof, and he has not time to 

 puzzle out the intricate theory given by Hertz. Mr. 

 Dellinger gives a rough proof of this formula based on 

 well-known laws. This formula being accepted, the 

 rest of radio theory follows very simply. The 

 formula has been tested in practice many times, and 

 found accurate within a small percentage of error. 

 NO. 2621, VOL. 104] 



■; The author makes a theoretical comparison of the 

 relative values of antennae and closed coils for sending 



' and receiving purposes, and it is shown how the 

 limitations of each follow directly from theory. 

 Although the theory is sufficiently accurate to be a 



; great help in the design of radio stations, yet the 

 necessity for further research, both experimental and 

 theoretical, is urgent, and a long list of such researches 

 is suggested. To everyone desiring a knowledge of 

 the practical theory of radio communication this paper 

 can be recommended. 



The lot of the inventor is always hard unless he is 

 exceptionally placed, and combines commercial with 

 inventive ability. Engineering for January 9 points 

 out two ways in which it is becoming increasingly 

 difficult. Experiment is becoming much more costly, and 

 at the same time the protection afforded by the patent 

 laws becomes less and less. Nevertheless, the essential 

 importance of invention from the national point of 

 view is now recognised, and research laboratories are 

 being set up which are to afford every facility for 

 experiment. The success of this movement depends 

 upon getting the inventors into the laboratories, and 

 upon their doing their best work when they are there. 



j But we find that men entering these laboratories are 

 being required to sign away all rights of every kind 



I to any invention they may make. They are to rely 

 solely upon a reward at the discretion of the firm. 



; Our contemporary suggests that a research laboratory 



[ should be an independent organisation, financed by the 

 parent firm, but receiving royalties on a liberal scale 

 to be divided among its members by agreement among 



I themselves, and also hints that it may be useless to 



I put forward such a scheme. Apart from the fact 



: that the British business man feels that he is less and 

 less "master in his own house," there is the other 



i point which appeals to research workers, viz. victimisa- 

 tion ; he may find himself no longer required in the 



I laboratory, and, after his discharge, may look in vain 



I for his share of the royalties. 



Engineering for January 9 contains an article on 

 \ works management by Mr. F. C. Van Dyke, which 

 will be found to give a very clear discussion of the 

 principles involved. There is a growing tendency to 

 j demand that the works manager should be a coUege- 

 i trained engineer, but it is essential that he should have 

 the same practical and varied engineering experience 

 as is required from the self-made man ; whatever may 

 have been his initial training, however, mere oppor- 

 tunity without fitness will not produce the successful 

 works manager. The requirements as regards his 

 ; principles and education may be summarised as con- 

 sisting essentially of organisation, foresight, co-ordina- 

 tion, supervision or control, and diplomacy. A works 

 ! manager should recognise that, notwithstanding 

 ' scientific effort and research, the efficiency given by 

 plant and machines is regulated by human effort, 

 wasteful by instinct, and that to obtain the reduction 

 of such waste it will be necessary to save lost efforts, 

 so that the recovery of waste may add new resources 

 to the community. He must also understand that 

 science in industry will generally be resented by the 



