The series of letters is part of Mullock's Historical Documents Sale at Ludlow Racecourse on May 22.
It also includes another set of 27 autographed letters to Vijaya Lakshmi Pandit, the sister of Jawaharlal Nehru, some written by Gandhi from prison.
“Women have done more work than us. Even so much remains to be done. The modern world has as yet seen the like of India's woman power. I am convinced they will go much further ahead and I will be very surprised if you do not play a very big part in this,” reads a letter dated November 11, 1930.
The earliest letters date back to 1920 but others are from the 1930s and the majority dating from the crucial period of 1938-1944 in the Indian national movement.
They are also mostly in Gujarati with a couple in English.
