76 



C. Bants — Coronas with Mercury Light. 



where n' \& the optical value of the number of nuclei per cubic 

 centimeter. 



In parts I-IV the angular diameter, s', of the green discs 



only were measured. The diameter s of the corresponding 

 first minims may, however, be obtained by using the method of 

 reduction found in parts V and VI where s='44+ '85 s'. 

 In parts V and YI the data for s' and s'\ the angular diam- 



