Apkil 6, 1900.] 



SCIENCE, 



551 



most important work was done between 1842 

 and 1855. Among other things, he showed that 

 in fluid motion the conditions under which the 

 equations of motion were integrable were the 

 conditions that the motion should be irrota- 

 tional. He made researches in the elastic 

 solid theory of light. He made advances in the 

 theory of physical geodesy. He showed that 

 the shape of the earth's surface should determine 

 the law by which gravity varied from place to 

 place. He cleared up a good many obscurities in 

 the work of Fourier in regard to Fourier series. 



The Jubilee began with the Eede lecture de- 

 livered by Professor Oornu, of the Ecole Poly- 

 technique, on the 'Wave Theory of Light,' 

 and its influence on modern physics. Besides 

 dinners, garden parties, etc., the most impor- 

 tant ceremonies were the presentation of ad- 

 dresses by the delegates representing about 

 seventy institutions, and the conferring of the 

 honorary degree of Doctor of Science upon 

 Messrs. Cornu, Darboux, Michelson, Mittag- 

 Leffler, Quincke and Voigt. At the dinner 

 which ended the celebration, Sir George Stokes 

 made a speech in the course of which he said 

 that he wished he had done more scientific 

 work, but that if he had, he might not have 

 been there to celebrate his Jubilee. 



Mr. A. C. Longden read a paper on the re- 

 sistance of thin films deposited by kathode 

 radiation. He described his method of deposit- 

 ing thin films on glass and showed some speci- 

 mens. These films can be used as high resist- 

 ances instead of the very expensive wire 

 resistances ordinarily used. Films of gold or 

 platinum can be deposited, which have not the 

 lack of durability of alloys. At the same time, 

 unlike the metals in the form of wire, they have 

 very low positive or even negative temperature 

 coefficients. The films are deposited from a ka- 

 thode of the same material by the discharge of 

 electricity through a vacuum, and can be depos- 

 ited in any thickness desired, and of any metal, 

 gold and platinum being however the most con- 

 venient. The speaker showed a gold film of 

 varying thickness in different parts, the thickest 

 part showing the green color like gold leaf when 

 viewed by transmitted light, and the color vary- 

 ing through blue to violet as the film became 

 thinner. 



At the suggestion of Mr. C. C. Trowbridge, 

 Mr. Longden attempted to deposit a thin con- 

 ducting film of selenium, but he was unsuccess- 

 ful, as the film deposited was non-conducting. 

 He obtained, however, a film of varying thick- 

 ness which exhibited the phenomenon of New- 

 ton's rings in a beautiful manner. 



An election of officers of the Section was 

 held. Pi'ofessor William Hallock was elected 

 Chairman, and Dr. William S. Day, Secretary, 

 for the ensuing year. 



William S. Day, 

 Secretary of Section. 



THE TOEREY BOTANICAL CLUB. 



At the meeting on February 18th, a paper 

 was presented by Dr. H. H. Kusby, entitled 

 ' The Tendency of Entomophilous Flowers to 

 Antero-posterior Irregularity.' Its object was 

 to show the distribution among plant-families of 

 cases of such irregularity. Irregularities origina- 

 ting without reference to insect-pollination were 

 classified and excluded. The irregularities con- 

 sidered and connected with insect-pollination, 

 are not found among the 21 lowest of the 43 

 families of monocotyledons. Of the 10 next 

 higher, 5 show none, 4 show slight or doubtful 

 forms, while the highest, Liliacese, with 197 

 genera, twice as many as the other 9 families 

 combined, shows, amidst general regularity, a 

 few highly irregular genera, two of them simu- 

 lating Orchidaceous forms. Of the 12 highest 

 families, only 3 are regular. Five of the high- 

 est 6 are very irregular, indeed, the highest, 

 OrchidaceiB, phenomenally so. It thus appears 

 that an increased tendency to irregularity is in- 

 dicative of higher development, but it is liable 

 to occur iu families and groups of families usu- 

 ally distinguished for its absence. 



This principle was then shown to be even 

 more clearly illustrated by the dicotyledons. 

 In the 53 lowest families, but 4 show irregu- 

 larity. Only one of these is found among the first 

 39, and this is AristolochiaceiE, with a single 

 irregular genus. Among the next 120 families, 

 27 show irregularity, and these are rather uni- 

 formly distributed among the others. Then come 

 19, several showing slight irregularity and one 

 very irregular, indeed. The next 17 are, with 

 one exception, highly irregular, one of themj 



