402 
MR. LOUIS VESSOT KING ON THE SCATTERING AND 
Tablk I .—Coefficients of Attenuation for JVashington, Mount IVihon, Mount TfAntney, and Potsdam. 
The table of constants of solar intensities and coefficients of attenuation for Washington, Mount Wilson, 
and Mount IVhitney is taken from the revised reductions based on the most recent observations of the 
Smithsonian Astrophysical Observatory.* * * § The unit expressing the relative intensities of solar radiation 
between wave-lengths A. and \ + dX is arbitrary, and can be reduced to calories per square centimetre per 
minute by multiplying by a factor r; such that 
->7 ScZA = 1 -922 calories per square centimetre per minute.t 
Jo 
In terms of the unit of intensity given in the table, and taking dk = • l/r, we find by graphical integration 
I Sc/A = 3321-0, so that r/ = -000578. 
J 0 
No accoiuit is taken of the water-vapour bands which occur mainly in the infra-red, where the intensity 
of solar radiation is comparatively small. The position and extent of these bands is shown in the curve 
of the intensities in the normal solar spectrum given in Vol. II. of the ‘ Annals.’J 
The transmission coefficients for Potsdam are those given l)y Muller.§ 
* Abbot, C. G-., “ The Sun’s Enorgj-Sjjecfcrum and Temperature,” ‘Astrophysical Journal,’ XXXIT., October, 1911, p. 197. 
t Abbot, C. G., and Fowlb, F. F., “ The Value of the Solar Constant of Radiation,” ‘Astrophysical Journal,’ XXXllI., 
April, 1911, p. 191. 
J ‘ Annals,’ vol. IF., p. 104. 
§ AlijLi.EK. G., ‘ Ilie Photometrie der Gestirne,’ Leipzig, 1897, ji. 138 
