Slipher, V. M., V. M. Slipher top Edwin Hubble, July 30, 1940, in response to Hubble's catalog of spectrographic images, 1940-07-30
Slipher states he will supply the images and information that Hubble has asked for but asks for a call to discuss a due date that he can send them by.…
Slipher, V. M., V. M. Slipher to Edwin Hubble, September 7, 1942, on Hubble's manuscript draft and multiple interpretations, 1942-09-07
Slipher thanks Hubble for sending him the draft of his paper on nebulae rotation and describes how he left some notes in soft pencil that Hubble could…