TABLE III. 



137 



Table III. — Observed Transmission of Benzaldehyde (CsHoCHO). 



[Sat., Mar. 21, 1903. Slits : Fi = 0.4 mm.; Fa = i mm. Thickness of cell, 0.06 mm.] 



[This compound has been selected at random, from the notes of the 125 -f" 

 compounds studied, as a typical example of the method of recording the original 

 observations taken in the laboratory. It is about the only compound whose trans- 

 mission spectrum has been explored to 16 /<. 



The direct deflections are of interest in showing the variation of the intensity of 

 the radiation of the "heater" of a Nernst lamp for different parts of the spectrum. 



For each compound such a set of deflections and spectrometer readings was 

 obtained, but in the following tables only the "observed transmission " and the wave- 

 lengths corresponding to the circle readings have been tabulated. This represents 

 some of the first work, when the spectrometer slits were much wider than for the com- 

 pounds studied later.] 



*27° 00' (Do" is the zero of the instrument ; i. e., when the sodium lines fell within the 

 radiometer slit the spectrometer circle reading was 27° o' 00" = 0.5896 //. 



