April 26, 1918] 



SCIENCE 



417 



Hilger spectrograph of the autocolimating 

 type, with very large prisms, and apparently 

 capable of yielding excellent spectra on a large 

 scale. The members of the regular staff of 

 chemists at the Station, under the direction of 

 Dr. K. B. Moore, are too much occupied with 

 their regular duties to undertake special spec- 

 troscopic researches. Therefore this fine in- 

 strument has not been utilized as it might be. 

 An unusual chance is thus presented for the 

 establishment of a fellowship for spectroscopic 

 research, under the joint auspices of the sta- 

 tion and of some university, physical labora- 

 tory or scientific fund. 



A second consideration of immediate im- 

 portance lies in the fact that Golden is situ- 

 ated near the central line of the total eclipse of 

 June 8. American science could be accused of 

 grievous neglect, if this spectrograph, already 

 in the eclipse track, should not be used on that 

 occasion by an expert spectroscopist. To many 

 such I have written personally during recent 

 months, urging that the opportunity be im- 

 proved; but as a result of war duties or the 

 shortage of assistants in the laboratories, thus 

 far no one has been found who could under- 

 take the work. 



It would be necessary for the person to go to 

 Golden early enough in May, so that the spec- 

 trograph could be put into excellent adjustment 

 and then to mount it where a clear view of the 

 northwestern sky could be had. The necessary 

 heliostat coiild doubtless be borrowed from 

 some laboratory. The altitude of Golden is 

 5,700 feet, and if the foliage around the sta- 

 tion building was too heavy in June, it would 

 not be at all difficult to transport the spectro- 

 graph up to an elevation of about 7,500 feet 

 on Lookout Mountain, where Colonel Cody was 

 "buried. 



The ideal arrangement will of course be for 

 this same person who gets familiar with this 

 spectrograph to continue in research with it 

 after the eclipse. K a suitable person is found, 

 an effort can be made to raise the necessary 

 funds for a fellowship or other basis which may 

 be arranged for the work. 



Time might perhaps be saved for those who 

 may wish to consider the observation of the 



eclipse with this instrument, if they will write 

 to me directly. 



I am writing this at the request of Dr. 

 Charles L. Parsons, of the Bureau of Mines, 

 and Dr. Moore. Edwin B. Frost 



Terkes Obseevatort, 

 WiixuMS Bay, 'Wisconsis, 

 AprU 13, 1918 



THE DESICCATION OF THE EARTH 



To THE Editor of Science : In Notes on 

 Meteorology and Climatology in the issue of 

 Science for October 21, 1910, attention is in- 

 vited to an article in Umschau by Dr. Karl 

 Stoeckel which helps to explain the slow desic- 

 cation of the earth. 



It is believed that the ultra-violet rays of sun- 

 light which fall upon the water vapor suspended 

 in the lower strata of the earth's atmosphere de- 

 compose a small part of it to produce hydrogen, 

 which rises to great heights. . . . 



I do not think it has been pointed out be- 

 fore that the earth's surface must be contin- 

 uously losing hydrogen through the decompo- 

 sition of water vapor by every flash of light- 

 ning. Pickering and others have recognized 

 the hydrogen lines in the spectrum of light- 

 ning, and the larger works on meteorology 

 mention the fact that lightning flashes decom- 

 pose some water. See Hann's " Lehrbuch der 

 Meteorologie," 2d edition, page 480: 



But the electric flash also decomposes some water 

 and causes the incandescence of the hydrogen. 



The hydrogen formed by every lightning flash 

 rises rapidly to the upper atmosphere and is 

 lost to the earth. 



Considering the frequency of thunderstorms 

 during the summer season in both hemispheres 

 and at all times in the equatorial regions the 

 loss of hydrogen in this way can not be con- 

 sidered as insignificant. As long as conditions 

 \i-pon the earth remain such as to render thun- 

 derstorms possible, the slow desiccation of 

 the earth must continue. 



C. F. VON Herrmann 



AREAS OF AUDIBILITY 



To THE Editor of Science: Students of the 

 constitution of the atmosphere have published 



