January 30, 1903.] 



SCIENCE. 



179 



cate a strong easterly wind above the 

 equator, shifting suddenly, at about 20° 

 north and south latitudes, to southwest and 

 west. We do not know the depth of the 

 trades, and nothing about the vertical vari- 

 ations of temperatui'e and humidity over 

 the ocean, uor whether sudden changes in 

 these elements occur between the trade and 

 the anti-trade. 



The author proposes to investigate these 

 and other questions by means of kites 

 carrying self-recording instruments which, 

 flown from his observatory on Blue Hill, 

 near Boston, during the past nine years, 

 have much increased our knowledge of the 

 atmosphere in this region up to a height 

 of three miles. Experiments made bj^ 

 him in 1901, in flying kites from a steamer 

 crossing the north Atlantic, proved that in 

 this way observations coiild be obtained in 

 the upper air independently of the wind. 



He now desires to make these atmospheric 

 soundings between the Azores and Ascen- 

 sion Island, and is endeavoring to obtain 

 the funds necessary to charter and equip 

 a steamer, believing that in this way some 

 of the most important problems in meteor- 

 ology and physical geography may be 

 solved. * 



Anomalous Dispersion and Selective Ab- 

 sorption of Fuclisin: Wm. B. Carlmel, 

 National Bureau of Standards. Pre- 

 sented by D. B. Brace. 

 To give a brief and concise account of 

 this work, I may state that it consists of 

 a determination of the dispersion curve by 

 interferential means, and of the absorp- 

 tion by means of a Brace spectrophotom- 

 eter. The methods of procedure have 

 necessarilj' been somewhat novel because 

 fuchsin is so strongly absorbing that it is 

 not possible to determine the dispersion 

 curve in the usual manner. 



The chief difficulty in the determina- 

 tion of the dispersion curve by interferen- 



tial means is that the light of one path of 

 the interferometer, after passing through 

 the film, is so reduced in intensity, that it 

 is too weak to produce interference when 

 it meets the undiminished light from the 

 other path. By partly balancing up the 

 intensity of the two paths by means of 

 an absorbing screen, and by using a form 

 of interferometer which only allowed the 

 light to traverse the film once, and which 

 rejected the enormous amount of light re- 

 flected from the surface of the film, it was 

 found possible to obtain good fringes 

 throughout the visible spectrum. The re- 

 tardations were determined by means of 

 spectral bands, using a mica compensator. 



The absorption of the same specimen of 

 fuchsin was determined by means of a 

 form of spectrophotometer which allowed 

 an unusually great intensity of light to 

 be used. The absorption has only been, 

 determined in part before, because of the 

 difficiilties encountered. A complete de- 

 termination has been made throughout the 

 spectrum, which agrees quite well with the 

 values found by other experimenters in 

 the portion of the spectrum in which they 

 had made measurements. 



The work was done upon films of from 

 0.2 micron thick to 0.6 micron thick. The 

 thicknesses were determined from the in- 

 terference bands of thin films, and are 

 correct to within about four or five per 

 cent. 



The Coefficient of Expansio)i of Some 



Alloys of Nickel and Cast Iron: Theo. 



M. FocKE, Case School of Applied 



Science. 



In Appendix No. 6 of the report of the 

 Coast and Geodetic Survey for 1900, Mr. 

 E. G. Fischer describes a new precise level, 

 in which an alloy of nickel and cast iron 

 replaces the brass ordinai'ily used. 



The experiments described in this paper 

 M-ere undertaken to find the composition 



