May 27, 1909J 



NA TURE 



375 



and which is taken, in accordance with the experiments 

 of \"iollu, as 0-104 of the Carcel lamp. 



The unit of light at the Physikalisch-Technische 

 Rcichsanstalt is that given by the Hefner lamp burning 

 at normal barometric pressure (76 cm.) in an atmosphere 

 containing 8-8 litres of water vapour per cubic metre. 



The unit of light at the National Physical Laboratory 

 is that given by the lo-candle-power Harcourt pentane 

 lamp, which has been prescribed for use by the Metro- 

 politan Gas Referees, burning at normal barometric 

 pressure (76 cm.) in an atmosphere containing 8 litres of 

 water vapour per cubic metre. 



In addition to the direct intercomparison of flame 

 standards carried out recently by the national loboratories 

 in Europe, one comparison was made in 1906 and two in 

 1008 between the American and European units by means 

 of carefully seasoned carbon filament electric standards, 

 and as a result of all the comparisons the following 

 relationships are established between the above units : — 



The pentane unit has the same value within the errors 

 of experiment as the bougie decimale. It is i-6 per cent, 

 less than the standard candle of the United States of 

 America, and 11 per cent, greater than the Hefner unit. 



In order to come into agreement with Great Britain and 

 I'ranre, the Bureau of Standards of America proposed to 

 reduce its standard candle by 1-6 per cent., provided that 

 l-'rance and Great Britain would unite with .America in 

 maintaining the common value constant, and with the 

 approval of other countries would call it the international 

 candle. The National Physical Laboratory, London, and 

 the Laboratoire Ccntr.Tl d Electricite, Paris, have agreed 

 111 adopt this propos.-il in respect to the photometric 

 - t.Tndardisation which they undertake, and the date agreed 

 upon for the adoption of the common unit and the change 

 of unit in .America is April i, 1909. 



The following simple relations will therefore hold after 

 th.it date : — 



Proposed new unit=i pentane candle. 

 = I bougie decimale. 

 = I -American candle. 

 = 1-11 Hefner unit. 

 = 0-104 Carcel unit. 



Therefore i Hefner unit = 090 of the proposed new unit. 



The pentane and other photometric standards in use in 

 .America will hereafter be standardised by the Bureau of 

 Standards in terms of the new unit. This, within the limits 

 of experimental error, will bring the photometric units for 

 both gas and electrical industries in America and Great 

 Britain, and for the electrical industry in France, to a 

 single value, and the Hefner unit will be in the simple 

 ratio of 9/10 to this international unit. 



The proposal to call the common unit of light to be 

 m.-iintained jointly by the national standardising labora- 

 tories of America, France, and Great Britain the " inter- 

 national candle " has been submitted to the International 

 Electrotechnical Commission, and through it to all the 

 countries of the world which are represented on that 

 ■ ommission. 



It is hoped that general approval will be secured, and 

 iliat in the near future the lerm " international candle " 

 for the new unit w-ill have official international sanction. 



.At the anniversary meeting of the Linnean Societv on 

 Monday, the gold medal of the societv was presented to 

 Dr. F. O. Bower, F.R.S., regius professor of botany 

 in the University of Glasgow. 



We regret to announce that Dr. G. von Neumaver, 

 Foreign Member of the Royal Society, and for many years 

 director of the marine observatory at Hamburg, has died 

 at Neustadi, at eighty-four years of age. 



Ed.mosd H.allev, the second Astronomer Royal, died on 

 January 14, 1742, and was buried in the churchyard of 

 St. Margaret's, Lee by Blackheath, in the same grave as 

 his wife, who had died five years previously. In 1854 

 the memorial stone being much out of repair, the Com- 

 KO. 2065, VOL. 80] 



missioners of the Admiralty, who by that time had the 

 Royal Observatory in their control, evidently considered 

 the tomb as a national monument, and replaced the stone 

 by a new one, the old stone being removed to Greenwich 

 Observatory, where it is now to be seen attached to a 

 wall. By lapse of time the second stone now requires 

 renovation, and we are glad to know that the Com- 

 missioners of the Admiralty have under consideration the 

 question of the repairs to be done. 



An International Congress of Applied Photographv is to 

 be held from July 8-10 ne.xt at Dresden, in connection 

 with a photographic exhibition. Particulars may be 

 obtained from the secretary, Dr. Veisz, Winchelmann- 

 strass, 27, Dresden. 



We regret to see the announcement, from the Berlin 

 correspondent of the Times, that Prof. Wilh. Engelmann, 

 professor of physiology in the University of Berlin, died 

 on May 20, at sixty-five years of age. Prof. Engelmann, 

 who held a professorship at Utrecht for many years before 

 his removal to Berlin in 1897, was an eminent authority 

 upon muscular and nervous, especially cardiac, anatomy. 



Prof. C. D. Perrine, of the Lick Observatory, has 

 been appointed director of the Argentine National Observa- 

 tory, Cordoba. His work with the Crossley reflector is 

 to be taken over by Dr. H. D. Curtis, now in charge of 

 the D. O. Mills expedition at Santiago, and the latter 

 will be succeeded by Mr. J. H. Moore, of the Lick Observa- 

 tory. Prof. Perrine will arrive at Cordoba at the end of 

 this month, and he asks that all correspondence shall be 

 ■directed to him there. 



Prof. David Todd, of Amherst College, Massachusetts, 

 is about to undertake an experiment for determining the 

 composition of the air at high levels, and the cause of 

 mountain sickness. He intends to make several balloon 

 ascents in a closed car from Canton, Ohio, the interior 

 of the country being considered preferable owing to 

 freedom from seaward air currents. Rarefied air will be 

 pumped into the car to keep the pressure at normal. The 

 Aero Club of New England has offered Prof. Todd the 

 use of its new, balloon, the Massachusetts, of 56,000 cubic 

 feet capacity, for the purpose of his experiments. 



The Blue Hills Meteorological Observatory, near Boston, 

 is about to lose, by his resignation, the services of Mr. 

 Henry Helm Clayton, who has been in charge of it since 

 1894, and has made it one of the most important weather 

 stations in America. He is to be succeeded by Mr. .A. H. 

 Palmer, now at Harvard. Mr. Clayton intends to attempt 

 shortly a balloon trip from San Francisco to the Atlantic 

 coast, as a preliminary test of the possibilities of an air 

 voyage over the Atlantic. He believes that he can 

 accomplish these feats by taking advantage of an upper 

 air current which appears to flow constantly eastward at 

 a height of about two miles above the earth's surface. 



.An incident reported from Wisconsin suggests some- 

 thing of the possibilities latent in " Christian science " 

 and allied notions as a menace to public health. In the 

 Legislature of that State there was recently introduced a 

 Bill providing that, in connection with lessons in 

 elementary hygiene, the pupils in the " public schools " 

 should be taught how to avoid contagion and the commoner 

 ailments. There immediately poured in hundreds of 

 letters and petitions protesting against such a policy, as 

 it would give children the impression that disease was 

 real. The opposition was so strong that the Assembly 

 Committee on Public Health, in spite of the efforts of 

 three physician members, was intimidated into killing the 

 proposal at its first hearing. 



