August 24, 191 1] 



NATURE 



251 



and it is made quite clear that standardisation of flour 

 is impossible. Analyses made by Dr. Monier-Williams 

 ire quoted to show that the differences in protein and 

 mineral matter between the standard flours and the 

 household flours obtained from the same wheat are 

 very small. These analyses should serve once for all 

 to disprove the absurd claims made for standard bread 

 by the Bread Reform League and other food reformers. 

 According to Dr. Hamill, "entire" wheat flours do, 

 however, possess additional constituents due to the 

 presence of branny particles and germ which appear 

 to have a value of their own in nutrition. Whilst the 

 evidence on this point is as yet of the slenderest, it 

 is sufficiently sponsored not to be lightly dismissed, 

 and further experimental work is urgently needed. 



Sufficient has been said to show that the report gives 

 a very faithful summary of the present position of the 

 subject, and it should remain authoritative until new 

 experimental facts cause an extension of our know- 

 ledge of the obscure points. It is at all events clear 

 that our bread supply is the best available, and that 

 legislative action is not required. 



THE INTERNATIONAL COMMITTEE OF 

 WEIGHTS AND MEASURES. 1 



THE most interesting part of the account lately 

 published of the proceedings of the International 

 Committee of Weights and Measures at their recent 

 meeting at Sevres is the information given respecting 

 the work of the International Bureau of Weights and 

 Measures during the last two years. Among the re- 

 searches conducted at the Bureau may be mentioned 

 an investigation of the suitability of vitreous quartz 

 (fused silica) for metrological purposes, which was 

 undertaken at the instance of Sir David Gill. Al- 

 though the specimens experimented upon admitted of 

 being ground and polished with facility, it was found 

 quite impossible to engrave on them lines of perman- 

 ent shape and sufficiently fine to serve as the defining 

 marks of standards of length. Similar negative 

 results had been obtained at the National Physical 

 Laboratory by Dr. Kaye, who has, however, devised a 

 method of obtaining perfectly satisfactory defining lines 

 by depositing a layer of platinum on the silica and 

 engraving the lines on the platinum. 



The high price of platinum has led to investigations 

 being made with the view of finding a suitable substi- 

 tute for this metal in the construction of standard 

 weights. Tantalum, which resists all the strong 

 mineral acids except hydrofluoric acid, has been found 

 to satisfy the necessary requirements of permanence 

 and hardness, and it is suggested that a series of 

 standard weights of ioo grammes made of this metal 

 should be established for use in chemical research. 

 Their cost ivould probably not be more than one-third 

 that of iridio-platinum standards. 



Dr. Stratton, of the United States Bureau of 

 Standards, who is a member of the International Com- 

 mittee, communicated the results of investigations on 

 the spectrum of neon. These tend to show that the 

 vellow radiation of neon of wave-length 5S52 tenth 

 metres is much superior to the red radiation of 

 cadmium as a unit for interferential measurements. 

 Neon is also much more convenient to employ, as it 

 does not require preliminary heating to a high tem- 

 perature; it has a longer life, is less subject to acci- 

 dents, is more brilliant, and requires much less atten- 

 tion on the part of the observer. Dr. Stratton proposes 

 to make use of this radiation in a new determination 

 of the length of the metre. 



1 Comite International des Poids et Mesures. Proces Verbaux des 

 Seances. Deuxieme seYie, tome vi. Session de iqii. Pp. vii + 347. 

 (Paris: Gauthier-Villars, 1911.) 



NO. 2182, VOL. 87] 



The president of the International Committee, Dr. 

 Foerster, invited particular attention to the important 

 question of end measures of length. It was decided to 

 address a circular letter to the various bureaus of 

 standards requesting information as to their practice 

 in regard to these standards, and describing certain 

 patterns which the International Bureau regard as 

 suitable for general adoption in the interests of uni- 

 formity. The patterns include three types of 

 standards, viz., cylindrical plug gauges for measuring 

 small thicknesses, end bars of 12 mm. diameter with 

 spherical caps, for greater lengths, and plane-parallel 

 blocks or plates for either the greater or smaller 

 dimensions. The method of comparing end measures 

 which was first employed by Airy some sixty years 

 ago in connection with the reconstruction of the 

 Imperial Standard Yard, has recently been tried at the 

 Bureau, and has been found to give very satisfactory 

 results. The verification of a series of gauges with 

 plane ends, made by the Swedish firm Johansson, has 

 demonstrated the extraordinary degree of accuracy 

 which can be attained in the construction of gauges of 

 this form. 



There are several important appendices to the 

 Proces Verbaux. The first, by Drs. Benoit and Guil- 

 laume, is an account of recent experiments with invar 

 measuring wires. The growing popularity of these 

 wires for geodetic operations, and the consequent 

 demand for their verification and re-verification, have 

 necessitated an immense number of comparisons at the 

 Bureau, and the experience thus obtained has admitted 

 of definite conclusions being arrived at as to how far 

 the lengths of these wires under standard conditions 

 can be regarded as permanent. The investigations 

 show that in general the wires, when manipulated 

 with the care usual in geodetic work, retain their 

 original lengths well within one part in a million. 

 Where greater deviations were found to occur they 

 could ,in general be accounted for either by the small 

 graduated scales at the ends of the wire having become 

 in the course of use slightly displaced from their true 

 tangential directions, or else by the wire having been 

 used in regions bordering on the tropics, where it 

 would be exposed to quite abnormal temperatures. 



In the second appendix Dr. Guillaume describes a 

 comparator designed by him for rapidly testing both 

 line measures and end measures. The instrument, 

 which was destined for use in the Chinese weights 

 and measures service, in which both the metric and 

 the native systems are recognised, was constructed to 

 admit of measurements in both these systems to a 

 degree of accuracy of nearly o'oi millimetre. A simpli- 

 fied form of this comparator, intended for use in 

 testing metric measures only, has also been designed 

 by Dr. Guillaume, and promises to be a convenient 

 apparatus for making rapid comparisons with a fairlv 

 high degree of accuracy. A measuring machine 

 suitable for use in manufactories for checking work- 

 shop standards or for general purposes is also described 

 by Dr. Guillaume (appendix 3). 



The flexure of the 4-metre geodetic standard at the 

 Bureau has been determined. This measure, which 

 is made of invar, has a section of the H-form, the 

 outside dimensions of which are about 4 centimetres. 

 The results of the observations on this bar exhibited 

 remarkable agreement with the calculated values based 

 on the Euler-Bernoulli theory" of the deflection of 

 elastic beams (appendix 4). 



The fifth appendix deals with the recent progress 

 of the metric system of weights and measures. On 

 January 1 last Bulgaria joined the Metric Convention, 

 raising the number of contracting States to twenty-five. 

 The metric carat of 200 milligrams has, up to the 

 present, received express legal sanction in nine 



