550 



NATURE 



[October 2, 189c 



1 



Fig. 7.— Periods 2 to i. Apastra coincident. 



Fig. 9. — Periods 5 to 3. Perlastra coincident 



i 



Fig. 8.— Periods 2 to i. Ap.istra not coincident. 



Fig. 10. — Periods 5 to 3. Periastra not cjincident 

 a Principal swarm, t. Subsidiary swarm, c Result in added light-units, d. Result in added magnitudes. 



