474 



SCIENCE 



[N. S. Vol. XXX. No. 771 



can it take in the work of promoting the gen- 

 eral welfare of children? Besides there are 

 ever with us the great questions of the course 

 of study and methods of learning — the what 

 and the how of teaching. In collecting and 

 reporting the more successful experiments 

 which are being made in the schools of any 

 part of the world, the Bureau of Education is 

 doing an incalculable service in making well- 

 established scientific formulations of educa- 

 tion possible. Special help is needed in the 

 study of ways and means for the teaching of 

 inorality and the elements of law that no child 

 ■may grow up without being well grounded in 

 the knowledge of the fundamental relations of 

 liuman beings. The office of the Commissioner 

 of Education has always been wisely and ably 

 administered. It has been of immense assist- 

 ance in promoting education in the United 

 States. It is reaching out to a larger work. 

 The time is ripe for it. But to do it, the 

 Bureau of Education must have larger appro- 

 priations, more experts, and above all, a much 

 larger authority and function in the service 

 of the nation. 



E. C. Moore 

 Xos Angeles, Cal. 



WATER VAPOR IN THE ATMOSPHERE OF 

 THE PLANET MARS'- 



An expedition from the Lick Observatory, 

 University of California, was recently sent to 

 the summit of Mt. Whitney, the highest point 

 of land in the United States, through the 

 private generosity of Eegent Wm. H. Crocker. 

 It had for its purpose to study the question of 

 water vapor in the atmosphere of the planet 

 Mars. The instruments consisted of a six- 

 teen-inch horizontal reflecting telescope and a 

 suitable spectroscope. The observations, made 

 on the nights of September 1 and 2, were 

 mainly photographic. 



Water vapor in the atmosphere of any planet 

 causes dark bands to be formed at certain 

 definite positions in the spectrum of that 

 planet; conspicuous bands if the water vapor 

 is abundant ; inconspicuous bands if the quan- 



"^ Statement by Director W. W. Campbell, of the 

 liick Observatory, prepared for the Associated 

 Tress. 



tity is slight, as this, the only method known, 

 is not a sensitive one. 



The observer of Mars must look up through 

 the earth's atmosphere ; and the great quantity 

 of water vapor in our atmosphere, if the ob- 

 server is near sea level or at ordinary altitudes, 

 blots out the effect of any Martian vapor, 

 making a solution of the problem impossible. 

 By ascending Mt. Whitney, altitude 14,501 

 feet, the Crocker expedition placed itseK above 

 probably four fifths or more of the earth's 

 water vapor. Further, the air on Mt. Whitney 

 was astonishingly dry during the time of the 

 observations. With barometer lYi inches, air 

 temperature 29 degrees Fahrenheit, and wet 

 thermometer lY degrees, students of the at- 

 mosphere will recognize that the observers of 

 Mars were looking through remarkably little 

 terrestrial water vapor. Even this small quan- 

 tity would be almost fatal to success if we did 

 not have a fairly satisfactory method of elim- 

 inating its effects, as follows : Our moon has 

 no appreciable atmosphere. The lunar and 

 Martian spectra will be affected alike by the 

 water vapor in the earth's atmosphere. These 

 spectra are photographed, one immediately 

 after the other while the conditions in our 

 atmosphere remain unchanged, and with the 

 moon and Mars at the same altitude above the 

 horizon so that their rays traverse equal paths 

 in our atmosphere. If the vapor bands in the 

 Martian spectrum are found to be stronger 

 than in the lunar spectrum. Mars has water 

 vapor in considerable quantities. If the bands 

 in the two spectra are equally strong, water 

 vapor on Mars does not exist in sufficient 

 quantities to be detected by the spectroscopic 

 method. The latter condition was found to 

 exist, when this method was applied under the 

 superlatively favorable conditions existing on 

 Mt. Whitney. Both spectra were photo- 

 graphed when Mars and the moon were near 

 the horizon, again when they were at medium 

 altitudes, and finally when they were 49 de- 

 grees above the horizon. The best vapor band, 

 technically called " a," was faint in both spec- 

 tra when the bodies were low, fainter when the 

 bodies were higher, and very faint when the 

 bodies were at their highest; but for equal 

 altitudes the " a " bands in the Martian and 



