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.…
Hubble, Edwin, Edwin Hubble to V. M. Slipher, July 27, 1942, on the draft of his paper "The Direction of Rotation of Spiral Nebulae", 1942-07-27
Hubble sent Slipher a copy of a revised paper for possible edits, emphasizing that he would revise it again based on specific spectrographic rotations…
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…