;50 



NA TURE 



[August 13, 1896 



doubt whether this is an iiiiproven.cat on the- usual 

 practice. 



The chapters on the flora of East Africa, and those on 

 the Zanzibar! and other natives of the country, contain a 

 large amount of information, and are thoroughly read- 

 able. The ^ame may be said of the concluding chapter 

 on the national mo\ements and future prospects of 

 British East Africa. The whole book is clearly and well 

 written and liberally illustrated, and the author, who quotes 

 - and quotes ap])ositely- not only Shakespeare, Byron 

 and (loethe, but also Carlyle, Buckle, and Rudyard 

 Kipling, has evidently gleaned widely in literary as well 

 as in scientific fields. ' VV. T. Blanford. 



THE MEETING OF THE INTERNATIONAL 

 COMMITTEE OF THE CARTE DU CIEL.^ 



i\ T the fourth meeting of the International Committee 

 '»■ of the Carte du Ciel, which took place at the Paris 

 Observatory in May, under the presidency of M.Tisserand, 

 the following members x\ere present : MM. Anguiano, 

 Bailland, Bakhuyzen, Christie, Donner, Duner, Gill, 

 Henry (Paul), Henry (Prosper), Loewy, Rayet, Ricco, 

 Trcpicd, Turner, X'iniegra. There were also present at 

 the invitation of the Permanent Committee, MM. Abney, 

 liacklund, Bouguet de la Grye, Callandreau, Common, 

 Cornu, Downing, Fabrc, P'aye, Gautier (P.), Jacoby, 

 Knobel, Lais, Laussedat, Newcomb, Perrotin, Scheiner, 

 Stephan, Wolf. 



Of the eighteen observatories associated for the pro- 

 duction of the Carte du Ciel, thirteen were represented. 

 The directors of the five other observatories, MM. Russell 

 (Sydney), Baracchi (Melbourne), Obrecht (Santiago), 

 Cruls (Rio Janeiro), Beuf (La Plata), were prevented from 

 attending by great distance or by professional duties. 



The following officers were elected : President, M. 

 Tisserand ; Vice-Presidents, MM. Bakhuyzen and Gill ; 

 Secretaries, MM. Donner and Trdpied. 



The following resolutions were adopted : — 



/. — Photographic Catalogue. 



1. The Committee is of opinion that the probable error 

 of the value of the rectilinear coordinates measured on 

 the plates should be reduced to the smallest possible 

 limits, and that the measurements must be directed in 

 such a way that this probable error shall never exceed 

 o""20. 



2. ((?) The Committee thinks it necessary to publish the 

 rectilinear coordinates of the photographed stars as soon 

 as possible. 



(b) It is desirable that this publication should include 

 the necessary information for the conversion of the results 

 into equatorial coordinates. 



(<-) The Committee desires that a provisional catalogue 

 of right ascensions and declinations should be published 

 by those observatories which have sufficient funds at 

 their disposal. 



3. Each observatory will be at liberty to choose the 

 positions of the comparison stars in the catalogues which 

 seem to them most suitable. For the calculation of the 

 constants of a plate, a minimum of ten comparison stars 

 should be adopted if possible. The adopted positions 

 of these coinparison stars will be published. 



4. The question of determining whether, for the reduc- 

 tion of the stars to 1900, it would be advisable to adopt a 

 uniform system of constants for the observatories, will be 

 the subject of a subsequent discussion. 



5. The Committee recommends the adoption of a 

 uniform size of publication for all the observatories ; the 

 size should be that of the volumes of the Catalogue of the 

 Paris Obserxatory. 



' .^bridged from Ihe liiilUtin Astronomiqtte^ July 1896. 



6. The observatories will be at liberty to determine the 

 photographic magnitudes, either by measurements or by 

 estimation. The only condition which the Committee 

 thinks it necessary to impose, is that the system of photo- 

 graphic magnitudes on which the measures or estimations 

 depend, should allow of a precise definition, so that the 

 different scales used in the different observatories can be 

 reduced io a common system. 



11— The Photographic Chart. 



7. Every observatory will be provided with a scale of 

 density, which will be printed on the plates at the same 

 time as the rcscaii, and which will permit the determina- 

 tion of the sensibility of each plate for luminous sources 

 of different intensities. 



Captain Abney is charged by the Committee with the 

 construction of the scales. 



8. For the construction of the chart, the second series 

 of negatives (that is to say, those of which the centres 

 have odd numbers for their declinations) will be made in 

 three exposures, each lasting thirty minutes. This time 

 of exposure may, of course, be reduced if an increase of 

 the sensibility of the photographic plates be secured. 



9. The Committee allows photogravure on copper as 

 a means of reproducing the chart. The negatives 

 to be exposed three times, and enlarged to twice the 

 original size. 



10. The observatories will make two positives on glass 

 by contact, one of which will be placed in the Pavilion de 

 Breteuil, the headquarters of the International Bureau of 

 Weights and Measures. 



11. The Committee defers till the next meeting the 

 examination of the measures which it may be necessary 

 to take with the object of assisting those observatories 

 which may anticipate a difficulty in completing their 

 programme. 



The meetings of the Committee were marked with 

 the greatest cordiality, and with the desire to carry to 

 the end the great work undertaken in common ; the 

 decisions, prepared by special sub-Committees, were 

 passed unanimously by the members present. 



The Conference was followed by a soiree on Saturday, 

 May 16, and by a dinner given the next day (Sunday, 

 May 17), in the large gallery of the Observatory, at 

 which the following were present: MM. Rambaud, 

 Minister of Public Instruction; Bertrand and Berthelot, 

 Permanent Secretaries of the Academy of Sciences ; 

 Cornu and Chatin, President and \'ice- President of the 

 Academy ; the members of the Committee, and numerous 

 visitors belonging to the Academy, the Bureau des 

 Longitudes, the Council of the Observatory, and the 

 pcrsoniicl of the establishment. Prof Backlund, Dr. 

 Downing, and Prof. Newcomb, members of the Conference 

 on fundamental stars, werfe also present. 



NO. 1398, VOL. 54] 



NOTES. 



Lieutenant he Gerlache announces that the Belgian 

 Antarctic Expedition he has been organising for .some time past 

 will not be sufficiently advanced to start before next year. 



M. EuGfeNE TissERANn will shortly retire from the post of 

 Director-General of Agriculture in France, after forty-six years 

 of public service. 



Extremely hot weather is reported from North America. 

 In New York, on Tuesday, the shade temperature reached 

 97° F. As many as 226 deaths are recorded as being 

 directly dvie to this abnormally high temperature. In Chic.igo 

 there were fifty-one deaths on Monday, and twenty-five on 

 Tuesday. Hundreds of dead horses are said to be lying in the 

 streets. The thermometer registered 96° F. at Ottawa. 



