PEITCHARD S WEDGE PHOTOMETER. 



315 



Bolometer, No. 16 (1 mm. aperture), accurately adjusted for the varying focus of each point in 



the spectrum. 

 Setting on Slit (before mounting prism) = 0° 0' 0". 

 D^ (after " " ) = 315° 48' 15". 



Current of Battery, 0.040 Ampere. 

 Eeader at Circle and Wedge, J. P. 

 " Galvanometer, F. W. V. 

 Watcher for Clouds, C. 

 Object = measurement of transmission of Pritchard wedge for different parts of the spectrum. 



Time, 11 a.m. to 2.15 p.m. 



TABLE IV. 



^0^4 



(Dev. 46° 40') 



Mean of Series 1 



0^.5 



< Dev. (44° 58') 



Mean of Series 2 



0*^.6 



(Dev. 44° 7') 



Mean of Series 3 



O".? 



No 

 Wedge. 



52.0 

 56.1 



54.1 



267.0 

 244.0 



256.0 



566.0 



588.0 



577.0 



799.0 



(Dev. 43° 37') 733.0 



Mean of Series 4 



> If.O 



(Dev. 42° 54') 



Mean of Series 5 



OM 



(Dev. 46° 40') 



Mean of Series 6 



766.0 



Wedge 

 at 0.3 in. 



12.7 

 13.3 



13.0 



68.4 

 65.9 



Wedge 

 at 1.8 in. 



1.9 

 1.1 



1.5 



9.0 

 9.7 



67.2 



157.0 

 158.0 



158.0 



311.0 

 319.0 



315.0 



933.0 

 10l40 



974.0 



42.9 

 42.6 



42.8 



578.0 

 581.0 



580.0 



8.6 

 9.8 



9.2 



9.4 



21.2 

 19.4 



20.3 



83.5 

 88.0 



85.8 



311.0 



288.0 



300.0 



1.5 

 1.1 



1.3 



Wedge 

 at 3.3 in. 



1.4 

 1.1 



1.3 



3.2 

 2.4 



2.8 



21.5 

 21.8 



21.7 



152.0 



158.0 



15^.0 



Wedge 

 at 4.8 in, 



0.4 

 0.2 



0.3 



5.1 

 5.1 



5.1 



83.0 

 80.5 



81.8 



Wedge 

 at 6.3 in 



1.0 



1.4 



1.2 



37.9 

 34.9 



36.4 



0''.6 



I Clouds prevented the completion of these series. 



>.0''.7 



(Dev. 43° 37') 



Mean of Series 7 



li^.O 



(Dev. 42° 54') 



Mean of Series 8 



756.0 

 721.0 



740.0 



948.0 

 896l) 



923.0 



299.0 

 286.0 



293.0 



468.0 

 572.0 



520.0 



78.5 

 79.0 



78.8 



260.0 

 282.0 



271.0 



19.8 

 21.7 



20.8 



143.0 

 150.0 



147.0 



5.1 

 5.9 



5.5 



78.8 

 85.5 



82.2 



1.1 

 1.1 



1.1 



31.9 

 37.2 



34.6 



