64 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



Fig. 6. — XSC 1-3-c. Increment for 1937. Complex lensing; two series of 

 concurrent lenses. Different sequences on different radii. 



Fig. 7. — YCt 2-5-a. Increment for 1940 (probably). Multiplicity; rather 

 complex situation of compound and concurrent lenses. 



