V. M. Slipher
Papers and correspondence of Lowell Observatory astronomer V. M. Slipher.
Slipher requesting Hubble's assistance and expertise with nebulae for a report to the International Astronomical Union. Includes suggestions for discussion of nebulae.
Hubble describes an addition he made to Mr. Hale's contribution on nebulae to an unspecified source. Hubble also indicates he is beginning a program to investigate nebulae.
Hubble describes characteristics of nebulae to Slipher and attempts to answer Slipher's questions. This includes types of nebulae and associated stars and measurements.