NO. 8 



WATER-VAPOR TRANSPARENCY FOWLE 



was made to agree with the other curve between 9 and 10 /a and 

 allowance has been made in it for the absorption and reflection losses 

 from the rock-salt prism and plate, as computed in table i. 



Table 8. — Comparison of Nernst Lamp and Black-Body Spectrum 



Wave-k-ngth ii : 



Percentage drop of lamp below black-body 



radiation 9 



Excess of transmission of lamp black over 



that at ID M 4 



Fig. II. — Ordinates are percentage absorptions, wave-lengths are indicated 

 at the bottom of the figure. Curve a, 75 cm. steam, 76 cm. pressure, 0.045 ppt. 

 H2O. Curve b, 20 cm. CO2, 76 cm. pressure. Work of Rubens and Aschkinass, 

 Annalen der Physik und Chemie, 64, p. 598, 1898. 



In the second line of the table are given vaktes for the percentage 

 excess of transparency of lamp black over that at 10 /a. The values 

 were obtained with candle smoke, for a layer containing 1.8 mg. per 

 cm^. The figures are principally interpolated from values given 



