May i. 1913J 



NATURE 



value of systematic research in engineering works. 

 For example, in the heat treatment of steel, no 

 amount of rule-of-thumb or the possession of an 

 expert eye could ever ensure uniformity in results 

 which vary enormously with but slight alterations 

 in temperature; some system of pyrometry is called 

 for as a protection against failures. The president 

 suggests the establishment of an engineering research 

 committee with a view to coordinate the work, to 

 prevent overlapping, to ensure the carrying out of 

 individual researches to absolute results, and to pub- 

 lish such results. In time the committee would 

 acquire so large an accumulation of data as to make 

 it the first source upon which the public would draw 

 for information as to any research already effected, 

 and as to the possibilities of extending research on 

 lines which might seem to require investigation. 

 The success which has attended the engineering- 

 standards committee might be regarded as holding 

 out possibilities of success for an engineering research 

 committee. 



The Cambridge University Press will publish 

 shortly a book on "Rubber and Rubber Planting," by 

 Dr. R. H. Lock, dealing with the history of the use 

 and cultivation of rubber, its botanical sources, the 

 botanical physiology of rubber and latex, the diseases, 

 chemistry, and manufacture of rubber, and with 

 rubber planting. 



The April edition of the catalogue of second-hand 

 scientific instruments which are for sale or hire at 

 the establishment of Mr. Charles Baker, 244 High 

 Holborn, London, W.C., has reached us. The list 

 includes some 2000 items, and an examination of the 

 catalogue shows that customers can obtain second- 

 hand "practically every class of scientific instrument. 

 Every instrument in the second-hand department is 

 guaranteed to be in adjustment. 



The Sun's Polar and Equatorial Diameters.— 

 The Annates de I'Observatoire [stronomique de Lose 

 (China), tome vi., contains three parts, the second 

 of which is devoted to an account of a photographic 

 study of the polar and equatorial diameters of the 

 sun as deduced from observations mad'- during the 

 period of 1905-10. The investigation was carried out 

 by Le R. P. S. Chevalier, S.J., and had for its first 

 object the discovery, if possible, of variations in the 

 mean diameter of the sun. The results obtained may 

 be briefly summarised as follows : — There is a differ- 

 ence between the polar and equatorial diameter, the 

 former diameter being the greater of the two. This 

 difference does not seem to be constant, and the 

 variations indicated cannot, according to the author, 

 be attributed to errors of observation, and, so far as 

 he can see, must be due to the sun itself. Here are 

 the values for each of the six years : — 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences for May : — 

 May 1. 2oh. 24m. Mars in conjunction with the 

 Moon (Mars o° 48' S.). 



4. I2h. om. Venus in conjunction with the 



Moon (Venus i° 26' N.). 



5. qh. om. Jupiter stationary. 



7. ioh. 35m. Saturn in conjunction with the 



Moon (Saturn 6° 20' S.). 

 10. 2ih. 19m. Neptune in conjunction with the 

 Moon (Neptune 5° 21' S.). 



12. 9h. om. Uranus stationary. 



13. i7h. om. Venus stationary. 

 18. 3h. om. Mars in perihelion. 



23. ioh. 23m. Jupiter in conjunction with the 



Moon (Jupiter 4° 56' N.). 

 25. oh. 50m. Uranus in conjunction with the 



Moon (Uranus 3° 38' N.). 



29. ih. om. Saturn in conjunction with the 



Sun. 



30. 15I1. om. Venus at greatest brilliancy. 



31. 2h. 25m. Mars in conjunction with the 



Moon (Mars 3 9' S.). 

 31. 6h. 31m. Mercury in conjunction with 



Saturn (Mercury 2 4' N.). 

 NO. 2270, VOL. qi] 



With regard to the value of the mean diameter, he 

 obtains 31' 59-93", which differs somewhat from that 

 usually adopted, namely 31' 5926", on the authority 

 of Dr. Auwers, after a series of measures with the 

 heliometer. While Chevalier points out that there is 

 evidently a systematic error in one of the two sets of 

 measures, and it may be in the photographic series, 

 but he has not been able to trace it, yet, he asks, 

 is it quite certain that it is excluded from the helio- 

 metric series, these measures all being made with 

 instruments of the same type and short focal lengths? 



United States Naval Observatory. — We have re- 

 ceived a copy of the annual report of the Naval Ob- 

 servatory for the fiscal year 1912. This modest and 

 admirably concise account of the year's work of three 

 active and important departments, corresponding to 

 our Greenwich and Kew observatories and the Nautical 

 Almanac Office, merely forms appendix No. 2 to the 

 annual report of the chief of the Bureau of Naviga- 

 tion. The department of the Nautical Almanac, under 

 the direction of Prof. W. S. Eichelberger, U.S. Navy, 

 who represented the observatory at the Congres In- 

 ternational des Ephemerides Astronomiques, held at 

 Paris in 1911, has expressed, under authority of the 

 U.S. Congress, its willingness to adopt the pro- 

 gramme of exchanges of "data recommended at the 

 Paris meeting. Particulars are given of various sig- 

 nificant changes it is proposed to make in the American 

 Ephemeris and Nautical Almanac, beginning with 

 the edition of 1916. Considerable progress appears to 

 have been made in the adoption of the Sperry gyro- 

 compass in the U.S. Navy; six battleships and two 

 submarines are supplied with sets, and ten additional 

 sets have been ordered. The ordinary magnetic com- 

 pass is still retained in ships fitted with gyro-com- 

 passes. We are informed that the noon signal has 

 been transmitted by radio-telegraphy to ships at sea 

 since so long ago as January, 1905. Special atten- 

 tion is being devoted to making improvements in the 

 instruments of nautical astronomy. Among a long list 

 of novel apparatus we note that a gyroscopic artificial 

 horizon has been tried. 



