Halos. General theory of halos, by Charles S. Hastings; Beautiful halo display observed at Ellendale, N. Dak., by Frank J. Bavendick [with note by W. R. Gregg]; Boulder halo of Jan. 10, 1918, Grand Junction halo of Mar. 3, 1906, [and] Outline showing formation of elements of halo complex, by Edgar W. Woolard.