May 8, 19 19] 



NATURE 



197 



sphere from one point to another. In this case signals 

 passing between two stations at a short distance apart 

 will traverse lower levels of the atmosphere than 

 those passing between stations separated by a great 

 distance. The eclipse probably affects the 'ionisation 

 of the upper and lower layers of the atmosphere 

 differently, and therefore we may expect to get 

 different effects on long- and short-range signals. 

 Moreover, it has been shown to be probable that 

 long waves are more affected than short waves by 

 changes of the ionisation of the air through which 

 they travel. The elucidation of this point "is one of 

 the aims of the observations. 



Anyone desirous of obtaining further information 

 should communicate with Dr. W. Eccles, honorary 

 secretary of the committee. City and Guilds Technical 

 College,' Leonard Street, London, E.C.2. 



THE BUREAU OF STANDARDS AND THE 



WAR. 

 'T* HE most obviously noteworthy feature of Dr. 

 J- Stratton's report on the work of the U.S. 

 Bureau of Standards for the year ended June 30, 1918, 

 is the very extensive field of investigation covered. A 

 large part of the work was necessarily related to the 

 war; the expenditure increased from about 140,000/. 

 in 1916-17 to more than 6oo,oooL in 19 17-18, of which 

 22o,oooL appears under the head of " National Security 

 and Defence," and is made up mainly of sums ex- 

 pended on new buildings and laboratories, additional 

 to the growth of ordinary expenditure due to war 

 conditions. The value of the tests made, chiefly for the 

 Government, is given as 2o,oooL ; and the number of 

 persons employed as 1405, of whom 839 were engaged 

 in research and investigations specially authorised by 

 Congress. The figures are useful as an indication of 

 the expansion which has taken place. 



The report opens with a brief account of the func- 

 tions and organisation of the Bureau, which, if space 

 permitted, it would be interesting to review in 

 detail. It affords a valuable study in these days of 

 reconstruction. The functions of the Bureau are 

 stated to be the "development, construction, custody, 

 and maintenance of reference and working standards, 

 and their intercomparison, improvement, and applica- 

 tion in science, engineering, industry, and commerce " ; 

 while the standards are classified under the five 

 headings : standards of measurement, standard con- 

 stants, standards of quality (of materials), standards 

 of performance (of machines and devices), and 

 standards of practice. The relations of the work of 

 the Bureau to the public and to the Government 

 service are examined in a manner which brings out 

 prominentlv the important rdle the institution plays 

 in connection with the national life and industry. 



The remainder of the report, some 180 pages, deals, 

 for the most part in short paragraphs, with the in- j 

 numerable items of research and test work which 

 have received attention in the various scientific and 

 technical divisions. These departmental reports con- 

 tain little more, in many instances, than a concise 

 statement of matters investigated ; in turning over the 

 pages, among the many points of interest, a few only 

 can be selected for comment. A new equipment has 

 been provided for measuring expansion up to tem- 

 peratures above 900° C. The examination of mine- 

 scales, used for weighing coal mined, led to the detec- 

 tion and removal of serious errors due to faulty 

 weights, improper installation, and neglect in mainten- 

 ance. The testing of gauges for the Ordnance Depart- 

 ment was undertaken bv the Bureau, as in this 

 country by the National Physical Laboratory, though 

 on a much smaller scale than here. Branches ^vere 



XO. 2584, VOL. 103] 



established at New York and elsewhere, and the 

 manufacture of gauges was commenced. 



In the electrical department ignition in petrol 

 engines was studied, and improved porcelains for 

 sparking plugs, developed by the ceramic laboratory, 

 were put into production. A special method was 

 devised for determining the velocity of projectiles. 

 The method of "magnetic analysis" as a criterion of 

 the quality of steel has been further investigated and 

 applied in practice. The photometric work included 

 tests of field searchlights and the investigation of gas- 

 filled standards of spherical candle-power. For wire- 

 less work a new building was nearly completed. 

 Sound-ranging was among the problems taken up by 

 one of the electrical sections. An account is given of 

 the relation of the Bureau to municipalities and public 

 service commissions in securing safety and standardisa- 

 tion in connection with electricity and gas supply; 

 some particulars are included of the national electrical 

 safety code. The subject of electrolysis of underground 

 pipes', cables, and other metal structures from stray 

 earth-currents is prominently mentioned, and may need 

 to be taken up actively in this country. 



In the work of the heat department may be noted 

 the determination of refrigeration constants, including 

 the thermal constants of ammonia. The fire-resisting 

 properties of structural materials, reinforced concrete, 

 etc., under load were examined. An apparatus was 

 completed for strength tests of metals at temperatures 

 up to 800° C. The work on aeroplane power plant 

 included the construction of an altitude laboratory for 

 engine tests under reduced pressure and at various 

 temperatures, and a number of tests on engines have 

 been carried out. The construction of radiators has 

 also been the subject of research. 



The researches in the optics department have in- 

 cluded much spectroscopic work, dealing especially 

 with the red and infra-red regions of the spectrum, 

 landscape photographv with red-sensitive plates, 

 colour-filters, etc. The great value of red-sensitive 

 plates in penetrating haze has been demonstrated, and 

 another important characteristic of these plates is 

 said to be their power to detect camouflage designed 

 to defeat the eye. Quantitative, as well as qualitative, 

 methods of spectroscopic analysis have been _em- 

 ploved. Polarimetry has received much attention, 

 especially in connection with the estimation of sugar, 

 and interesting results have been obtained with regard 

 to the natural rotation of quartz at high temperatures ; 

 an abrupt change was found to occur at about 574° C. 

 In connection with the polarimetric work intense 

 monochromatic light sources were necessary, and, 

 after experiment with cadmium amalgam lamps, a 

 lamp using a new allov has been produced. A novel 

 method for the production of artificial daylight makes 

 use of the rotatory dispersion of quartz. 



A considerable amount of attention in the optics and 

 chemistry departments has been given to the produc- 

 tion of optical glass. The Bureau is said to be 

 shipping glass in quantity for the manufacture of 

 optical instruments. Some seven or eight varieties 

 of the most used glasses are being produced, includ- 

 ing a dense barium crown. For thi'= work a new 

 glass laboratory' was erected in 1017. Mik h invrstiga- 

 tion has necessarily been devoted in tliis cunnorfion 

 to the production of pots for melting. 



The work of the chemistrv section has inckidod the 

 study of electroplating and electrotyping ; the im- 

 provement of the electrolytic method of estimation of 

 carbon in steel so that an accurate determination can 

 now be made in 4^ minutes ; the testing of balloon 

 fabrics and the investigation of balloon gases, together 

 with chemical work on oils, rubber, paper, textiles, 

 ink, glue, cement, bitumen, and other materials. It 



