September 7, 1900.] 



SCIENCE. 



377 



Association, and the French Scientific Journals 

 do not contain any regular announcements or 

 reports of the meetings. The address of the 

 President, General Sebert, before the Paris 

 meeting is, however, published in several jour- 

 nals and the report of the Treasurer is printed 

 in full in the Eevue Scientifique. 



M. Sebert reviewed the progress of mechan- 

 ical science, and devoted the last third of his 

 address to an international catalogue of scien- 

 tific literature. It is rather curious that he 

 does not in any way refer to the International 

 Catalogue, but states that the problem is being 

 solved by the Institut International de Biogra- 

 phie, established by MM. Lafontaine and Otlet 

 in Brussels in 1895. The Dewey system of 

 classification is adopted by them, and M. Sebert 

 devotes a considerable part of hia address to 

 explaining the system which he advocates in 

 warm terms. 



The finances of the French Association are of 

 interest. The capital amounts to 1,326,917 fr., 

 chiefly due to legacies such as the American 

 Association has never received. The income 

 last year was about $17,000, -of which nearly 

 $7000 was income from the capital and about 

 $10,000 represented the dues of members. 

 These figures apparently are much more favor- 

 able than those of the American Association, in 

 which the income from permanent funds was 

 last year $233 and receipts from ;_members 

 $6216. It appears, however, that, owing to 

 the cost of the volume of proceedings and of 

 administration, the expenses of the French 

 Association are considerably larger than the 

 receipts from the annual dues of members, 

 whereas, during the past two years, the Ameri- 

 can Association has been able to transfer to the 

 permanent funds a portion of the dues received 

 from members. 



Although about half of the interest on the 

 capital is used for cvirrent expenses, there is 

 still a considerable sum — about $3000 — which 

 is annually awarded for the promotion of re- 

 search. Among the larger grants made last 

 year were : $300 to M. Giard for the publica- 

 tion of papers from the laboratory at Wimereux ; 

 $300 to M. Deniker for the publication of his 

 book on the races of Europe ; $240 to M. 

 Lacaze-Duthiers towards repairing the steam- 



boat of the zoological laboratory at Arago, and 

 $200 to M. Turpain for researches in tele- 

 graphy by Hertzian waves. 



THE ELECTRICAL EFFECTS OF LIGHT UPON 

 GREEN LEAVES* 



In the preliminary communication recently 

 made to the Royal Society, the author shows 

 how, from the study of the electrical effects of 

 light upon the retina, he was led to ask whether 

 the chemical changes aroused by the action of 

 light upon green leaves are also accompanied 

 by electrical efiects demonstrable in the same 

 way as the eye currents. The question is 

 tested in the following way : A young leaf 

 freshly gathered is laid upon a glass plate and 

 connected with a galvanometer by means of 

 two unpolarizable clay electrodes A and B. 

 The half of the leaf connected with A is shaded 

 by a piece of black paper. An inverted glass 

 jar forms a moist chamber to leaf and elec- 

 trodes, which are then enclosed in a box pro- 

 vided with a shuttered aperture through which 

 light can be directed. A water trough in the 

 path of the light serves to cut out heat more or 

 less. Under favorable conditions there is ob- 

 tained with such an arrangement a true elec- 

 trical response to light, consisting in the estab- 

 lishment of a potential difference between il- 

 luminated and non-illuminated half of a leaf, 

 amounting to 0.02 volt. 



The deflection of the galvanometer spot dur- 

 ing illumination is such as to indicate current 

 in the leaf from excited to protected part. The 

 deflection begins and ends sharply with the 

 beginning and end of illumination ; it is pro- 

 voked slightly by diffuse daylight, more by an 

 electric arc-light, most by bright sunlight. It 

 is abolished by boiling the leaf, and by the 

 action of an anaesthetic, carbon dioxide. 



The flrst experiments, made at the end of 

 March, were upon iris leaves taken from plants 

 about six inches high, and the response to light 

 was then between 0.001 and 0.002 volt in value. 

 Experiments upon similar leaves were resumed 

 early in May, when it appeared that the exter- 

 nal condition in which the state of the leaf is 



* Abstract of a paper presented before the Eoyal 

 Society by Augustus D. Waller, M.D., F.E.S., and 

 published in Nature. 



