752 



SCIENCE 



[N. S. Vol. XI. No. 280. 



The summer meeting of the Society will be 

 held at Columbia University, June 27th-30th in 

 connection with the meeting of the American 

 Association. F. N. Cole, Secretary. 



Columbia University. 



new york section of the american chem- 

 ical society. 



The regular monthly meeting of the New 

 York Section of the American Chemical Society 

 was held on Friday evening, April 6th, at the 

 Chemists' Club, 108 West Fifty-fifth street. 

 Dr. C. F. McKenna presided, and the following 

 papers were read ; 



' A Method of Obtaining Nucleic Acid,' by Dr. 

 P. A. Levene. 



' Analysis of a Saline Deposit from Southern 

 Nevada,' by Ealph W. Bailey. 



' Notes on the Ferrocyanide Titration of 

 Zinc,' by Dr. E. H. Miller and E. J. Hall. 



Special announcement was made of an extra 

 meeting to be held on May 2d, for the exhibi- 

 tion of novel forms of apparatus, products, etc., 

 and that the meeting would be in the nature of 

 a reception, to which the ladies and friends of 

 the members would be invited. The Section on 

 this occasion will be the guest of the Chemists' 

 Club. 



An invitation to attend the next meeting of 

 the New York Section of the Society of Chem- 

 ical Industry, to hear a paper on ' Petroleum 

 and its Products,' by Dr. C. F. Newberry, 

 signed by Dr. Parker, was then read, after 

 which the meeting adjourned. 



DuRAND Woodman, 



Secretary. 



DISCUSSION AND COEEESPONDENCE. 



PHYSICAL observations DURING THE TOTAL 



SOLAR ECLIPSE. 



To THE Editor of Science : While the 

 most important observations during the total 

 eclipse of the sun are, of course, astronomical, 

 some simple physical observations can be made 

 with little or no apparatus and may serve to 

 elucidate two obscure atmospheric phenomena, 

 namely, the so-called ' shadow-bands ' and 

 the changes in the direction and velocity of 

 the wind. 



Professor R. W. Wood, in Science of April 



27, has described the appearance of the shadow- 

 bands and has given instructions for observing 

 them, so that, although I myself had prepared 

 a circular of instructions for co-operating ob- 

 servers, yet, in consequence of the fact that so 

 able a physicist as Professor Wood will study 

 this phenomenon, I shall be glad to send him 

 my own observations and any that I may re- 

 ceive. It may be interesting here to state 

 briefly the results of the observations made and 

 collected by Professor Winslow Upton, Mr. A. E. 

 Douglass and myself during total solar eclipses. 

 In the eclipse of August 19, 1887, observed in 

 Russia, it was cloudy and no shadow-hands 

 were seen, but in the eclipse of January 1, 1889, 

 observed in California with a clear sky, the 

 bands were well defined, though an attempt to 

 photograph them failed. They were ' more 

 prominent at high altitudes than at low levels, 

 but they seem to have no connection with the 

 position of the stations in or near the shadow- 

 belt. While the reports of the various obser- 

 vers indicated a general agreement for the di- 

 rection in which the bands lay, yet there was 

 no uniformity in the direction of progression 

 which seemed not to be related to the direction 

 of the wind. In every case the speed of the 

 bands was much less than that of the shadow 

 itself, thus disproving the theory that the bands 

 are diffraction fringes in the shadow of the 

 moon. The observations are discussed by Pro- 

 fessor Upton and myself in Vol. XXIX., No. 1, 

 Annals Astron. Observatory of Harvard College. 

 During the eclipse of April 16, 1893, observed 

 in Chile under the most favorable circumstances, 

 the shadow-bands were very generally seen im- 

 mediately after totality. They lay approxi- 

 mately northwest and southeast, and moved 

 mostly towards the southwest at a speed vari- 

 ously estimated at from three to twenty miles 

 an hour. The width of the bands appeared to 

 vary from one-eighth of an inch to four inches, 

 and their distance apart from one to ten inches. 

 A significant fact was that, contrary to the ob- 

 servations in the previous eclipse, the bands 

 were much less conspicuous on the mountain 

 summit, occupied by the writer, than near sea- 

 level, where they were also coarser, thus indi- 

 cating the effect of increased thickness of at- 

 mosphere. 



