NO. 8 



WATER-VAPOR TRANSPARENCY — FOWLE 



57 



making a similar development for ({>^{x — ca), adding and transposing 



^."(;.) = ^-{*i(^±£f5)±M£;:i5_)_^,(,,.)|+. . . . 



which let equal, say, - ^ ^2(''*") ) but 



/-2/j2 



^^"{^)=^'fF'-(x) + 



Whence 



F'^(,r)= -^-1, </>"(■*■), approximately 



c-'a 





say 3 



^. *.(-)■ 



Substituting in (2) there results the following development of the 

 energy curve f(x) as, with certain reservations, it might be expected 

 to appear with an infinitely narrow slit and bolometer, in terms of 

 the observed energy curve F{x). 



+ 



i44ofe^^c^ 



^,{x) + 



When w=i, or the slit and the bolometer are of the same angular 

 width in the spectrum, which is Runge's case, the second half of the 

 above equation reduces to 



= F{x)- I <^,(.r)+ ^^~<}^,{x)+ 



The coefficients for the various cases in the present research were : 



Table 14. 



* Equivalent to differences of deviation as expressed in millimeters on the 

 holographs or energy curves. 



