548 



SCIENCE. 



[N. S. Vol. XV. No. 379. 



Mr. Trowbridge gave his views as to the 

 most probable composition of meteor trains, 

 and presented several hypotheses which might 

 account for their long-continued luminosity. 

 The hypotheses advanced were the following: 

 (1) Incandescence of the particles of the 

 train; (2) phosphorescence of the train; (3) 

 electrical discharges; (4) reflection of the 

 light from the sun, moon or stars by the par- 

 ticles of the train; (5) electrons striking the 

 n steoric dust or the air particles in or about 

 the train, causing a fluorescent glow similar 

 to that in a Orookes tube. The source of the 

 electrons may be either the highly heated 

 meteor, in which case the long-continued 

 luminosity of the train must be accounted 

 for by a retardation of the fluorescence, pos- 

 sibly due to the low temperature, or the elec- 

 trons may come from the sun; in this case 

 the explanation would be similar to that 

 lately given by Arrhenius for the light of the 

 aurora. The author stated that this last hy- 

 pothesis had not, so far as he knew, been previ- 

 ously advanced, and that the balance of evi- 

 dence seemed to show that the luminosity of 

 the persistent trains must be primarily caused 

 by energy of an electrical nature. The sub- 

 ject is one of practical importance, owing to 

 its bearing on meteorology. 



The paper by Dr. S. C. Mitchell gave the 

 results of observations on the flash spectrum 

 taken by him at Sawah Loento, Sumatra, dur- 

 ing the eclipse of May 18, 1901. Dr. Mitchell 

 became, by the courtesy of the astronomical 

 director of the Naval Observatory, a member 

 of the eclipse expedition sent out by this gov- 

 ernment. The spectroscope employed was a 

 Rowland objective plane grating of 15,000 

 lines, used in connection with a coelostat. The 

 weather experienced at Sawah Loento was 

 like that at almost every astronomical loca- 

 tion in Sumatra, cloudy throughout totality. 

 However, through clouds, a spectrum of the 

 flash at third contact was obtained which 

 showed 374 bright lines between F and H. 

 Investigations into the reasons for the differ- 

 ences of intensities in the flash and the Fraun- 

 hofer spectrum showed that the intensities 

 depend on the heights to which the reversing 

 layers of the different metallic elements 



around the sun extend. It was found possible 

 to arrange the elements in three groups ac- 

 cording to their atomic weights. 



Comparisons were made with Dr. Norman 

 Lockyer's list of 'enhanced' lines, or those 

 stronger in the spark than in the arc, in order, 

 if possible, to confirm Lockyer's idea that the 

 'enhanced' lines play an important role in the 

 chromosphere spectrum. Fifty-seven per cent, 

 of the 'enhanced' lines of titanium were found 

 in the flash, biTt at the same time all of these 

 lines corresponded without exception to 

 strong lines in the sun. ■ On the other hand, 

 so many cases were found where a strong 

 'enhanced' line was not matched in the sun 

 by a strong Fraunhofer line, nor by any line 

 in the flash spectrum, that it seemed that the 

 measures did not support Lockyer's opinion. 



Section adjourned. 



F. L. Tufts, 

 Secretary. 



THE ACADEMY OF SCIENCE OF ST. LOUIS. 



At the meeting of the Academy on the 

 evening of March 3, about thirty-five persons 

 present, Mr. L. T. Genung, of St. Louis, gave 

 a general discussion of the Lepidoptera, their 

 structural characteristics, habits and adapta- 

 tions. He exhibited some of the more strik- 

 ing specimens of the Denton collection of 

 butterflies, recently presented to the Academy 

 of Science, and discussed the meaning of the 

 various colors. 



A paper by Mr. 0. F. Baker, entitled 'A 

 Revision of the Elephantopese, I.,' was pre- 

 sented by title. 



Two persons were elected to active mem- 

 bership. 



William Trelease, 

 Recording Secretary. 



THE COLORADO ACADEMY OF SCIENCE. 



At the annual meeting of the Academy, 

 held February 11, 1902, in rooms of the State 

 Historical and Natural History Society, State 

 House, Denver, Colorado, ofiicers were elected, 

 and chairmen of sections appointed February 

 27, resulting in the selection of the following 

 for the year 1902: 



President, A. M. Collett; First Vice-President, 

 Mrs. Cornelia Miles; Second Vice-President, Z. X. 



