December 29, 1910] 



NATURE 



^^l 



a separate brochure. Photographs of the exhibits from 

 Harvard, Mount Wilson, Heidelberg, and other observa- 

 tories show that astronomy was fairly well represented at 

 the exhibition. 



Traci.ng the Solar Corona i.\ Lunar Observations. — 

 In the December number of the Bulletin de la Societe 

 astronomique de France M. Em. Touchet makes the 

 interesting suggestion that observers may be able to trace 

 the radiations of the solar corona in observations of the 

 moon. The note was submitted to the Academic des 

 Sciences in 1906, but did not appear in the Comptes 

 rendus, and even now M. Deslandres considers the difficul- 

 ties of realisation are about equal to those surrounding the 

 photography of the corona in full sunlight. 



The suggestion is that when the sun rises on the moon, 

 the lunar surface, owing to the absence of atmosphere, 

 would first be illuminated by fairly strong corona! light, 

 then by the chromospheric radiations, and lastly by the 

 photosphere. With the observer's spectroscope slit 

 delicately adjusted on the position of lunar strip lighted 

 by the corona, one might possibly find, in addition to the 

 ordinary lunar spectrum, a narrow sf)ectrum composed of 



AMERICAN HYDROGRAPHY.' 



'T'HE first impression which one gains in turning over 

 the pages of these seven reports is that, if genius 

 be, as Dr. Johnson asserted, an infinite capacity for 

 taking pains, then the compilers of these statistical records 

 possess that attribute in a very high degree. One turns 

 over page after page of systematically prepared data, un- 

 questionably the outcome of innumerable observations 

 which have been carefully and religiously made through 

 long periods of time, and one cannot but admire the 

 patient, painstaking zeal of these scientific workers who 

 have concentrated their energies on this special field of 

 enterprise, in the service of their country, for the develop- 

 ment of its resources and the expansion of its commerce. 



The work is carried on under the auspices of the Geo- 

 logical Survey of the United States, and this relationship 

 of hydrography to geology calls to mind the proud reply 

 of the " Scarabee " to the Poet at the Breakfast Table : — 

 " I am often spoken of as a Coleopterist, " he said, " but 

 I have no right to so comprehensive a name. The genus 

 Scarabaeus is what I have chiefly confined myself to, and 

 ought to have studied exclusively. The beetles proper are 



Hydro-electric Plant (developing 36,600 horse-power) on Puyallup River, near Electron, Washington. 



that of the earth-light and the corona. M. Touchet realises 

 that the difficulties are enormous, but suggests that, with 

 a clear atmosphere, large dispersion, and the large aper- 

 tures now available at Mount Wilson, for example, they 

 might not prove insuperable. 



Annual Publications. — ^The " Companion to the 

 Observatory," published by Messrs. Taylor and Francis at 

 15. 6d., contains the usual features, and should be secured 

 by every astronomical student actually engaged in making 

 observations. The increase in the number of variable 

 stars makes the publication of the complete list impossible. 

 -As the compilers of the " Annuaire du Bureau des Longi- 

 tudes " have discontinued the computation of the variable- 

 star ephemerides, the editors of the " Companion " can no 

 longer rely upon that source of information. 



M. Flammarion's " Annuaire Astronomique " also 

 follows its usual fbrm, and is a most useful work of refer- 

 ence to all interested in the popularisation of astronomy. 

 Its review of the past year's astronomy and meteorologv 

 is also useful, while the special articles therein comprised 

 are very interesting ; among them we might mention 

 notices on Halley's comet and the Paris floods of 1910. 



NO. 2148, VOL. 85] 



quite enough for the labour of one man's life. Call me 

 a Scarabeeist if you will : if I can prove myself worthy 

 of that name, my highest ambition will be more than 

 satisfied. " 



This is the true scientific spirit : the concentration of 

 thought and energy on one special branch of study to the 

 exclusion of even cognate interests ; the patient accumu- 

 lation of facts and data, and their careful analysis and 

 tabulation, within a purview sufficiently restricted for the 

 capacity of the individual investigator — by these means 

 alone is the practical knowledge of the world increased 

 and its avenues of progress extended. 



In order to appreciate the full utility of these records 

 it is essential to recall the fact that the development of 

 water-power in every civilised country is rapjdlv becoming 

 an economic necessity. With the steady depletion of coal, 

 lumber, oil, and natural supplies of fuel there arises a 

 corresponding need for the exploitation of other sources 



1 Surface Water Supply of the United States. 1907-S. Bulletins prepared 

 under the general direction of M. O. Leighton, viz., Paper No. 241, North 

 Atlantic Coast ; No. 243, Ohio River Basin ; No. 244, St. Lawrence River 

 Basin ; No. 245, Upper Mississippi and Hudson Bay Basins ; No. 24S 

 Western Gulf of Mexico ; No. 249, Colorado River Basin ; No. 252, North 

 Pacific Coast. OVashington : U.S. Geological Survey, 1910.) 



