This letter was about the list of photographs of Sun taken on different dates and at particular times mentioned.

The fond contain correspondance of M. K. Vainu Bappu with C. V. Raman and mentors, donated by Mrs. Yemuna Bappu to IIA archives.

This letter was to replying Dr.M. K. Vainu Bappu for telling the improvements required in the spectra for H & K emission.

This letter discusses on the predicted formula about the shifts of the solar lines in agreement with the observed values at the red end of the spectrum.

This Letter is from Astronomer Royal to the Director regarding sun photographs for 1911 May 19 and 20

The letter is from Astronomer Royal, Royal Observatory, Greenwich, London, to The Director, Kodaikanal Observatory, Madras, India, requesting to send solar photographs of the mentioned dates as the photographs taken from there are deficient.

This letter was to inform on M. K. Vainu Bappu's research on Sun. It also mentioned finding a location for the Solar Physics Observatory and also asking Bappu for the present address of Zeiss and of Cox, Hargreaves and Thomson.

This letter was about the conversations of C. M. Smith on sunspot article.

The letter was from Charles P. Butler to John Eliot the Meteorological Reporter to the Government of India and Director General of Indian Observatories, Simla, in 1903. The letter is about increasing the power of the apparatus used for sun-spot spectra of Kodaikanal Observatory.

This is a letter from Charles. P. Butler, Ag: Director, Kodaikanal & Madras Observatories to Executive Engineer Madura regarding some construction needs at the Solar Physics Observatory, like a permanent building to hold the 4-inch photoheliograph, a glazed verandah for keeping the north-western side of the observatory dry, an open verandah for the Bookbinder's shed and quarters for the writer of the observatory, on which the details will be given later when the decision is finalised.