640 



SCIENCE 



[N. S. Vol. XXXVII. No. 956 



for sea level, and the seeond is for the conditions 

 and altitude (1,780 meters) of Mount Wilson. 



Pressure of Aqueous Vapor 



^"=1.70 

 2.06 

 2.34 

 2.63 

 2.91 



1.76 

 2.16 

 2.45 

 2.75 

 3.05 



1.78 

 2.21 

 2.52 

 2.84 

 3.15 



1.80 

 2.25 

 2.58 

 2.90 

 3.20 



1.86 

 2.30 

 2.63 

 2.95 

 3.25 



These tables have been used to get the value 

 (^ = FB) of the solar radiation outside the at- 

 mosphere from observations published in Vol. 2 

 of the Annals of the Smithsonian Astrophysieal 

 Observatory. A random selection will illustrate 

 the nature of the results. 



Washington, D. C. 



The data are very inadequate. The pressure of 

 aqueous vapor is seldom recorded more than onee 

 a day, and in the absence of barometer readings 

 I have been obliged to assume values of 760 mm. 

 and 618 mm. for sea level and mountain, respect- 

 ively. To do full justice to the method, it will be 

 necessary to secure simultaneous observations of 

 the distribution of aqueous vapor in the upper air 

 by means of sounding balloon ascensions or high 

 kite flights. No correction for atmospheric dust 

 has been applied. The depression and the dis- 

 agreement of the sea-level results are no doubt due 

 principally to the irregular depletion by this in- 

 gredient of the lower air. This serious defect very 

 nearly disappears on the mountain. 



Astronomy m the Civil Court: W. F. Rigqe. 



A short time ago a man was accused in the 

 criminal court (Omaha, Nebraska) of having at- 

 tempted to wreck a cottage and kill its inmates by 

 means of a suitcase full of dynamite. The state 

 produced only two witnesses, who said they had 

 seen the accused carrying the suitcase near the 

 time and place specified. They had just come 

 from a church a mile away, in front of which 

 they had posed for their photograph. The position 

 of a prominent shadow in this picture enabled an 

 astronomer to compute the exact minute of its 

 exposure. As this was half an hour after the 

 time at which the suitcase had been found the 

 testimony of science eventually freed the prisoner 

 from fifteen years in the penitentiary. It was 

 confirmed by the measurements and computations 

 of a seeond astronomer, and by a series of three 

 photographs exposed at intervals of one minute 

 on the second anniversary of the taking of the 

 original picture. 

 A Northern Bnrchmusterung : E. C. Pickering. 



The Cape Photographic Durchmusterung gives 

 the positions and photographic magnitudes of 

 nearly half a million stars south of declination 

 — 20°, thus covering about one third of the sky. 

 This great work by Grill and Kapteyn is indis- 

 pensable to any astronomer studying the southern 

 stars. 



One of the greatest needs of astronomy at the 

 present time is the extension of this work to the 

 North Pole. A plan has accordingly been pre- 

 pared for taking the necessary photographs at 

 Harvard, with the 16-inch Metealf telescope, with 

 curved plates, using those sensitive to the red, as 

 well as to the blue rays. The photometric and 

 photographic magnitudes, on a uniform scale, will 

 be determined for a number of standard stars on 



