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 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 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.

This letter was about replying to C. M. Smith opinion on uselessness of a table in the solar article for the Monthly Weather Review.

This letter was with reference to the telegram where mean areas giving better gauge of prominence activity than mean extent are discussed. It also encloses a table of mean areas from 1890 to 1921.

This letter is a reply regarding the sun's entry into Aries from the Director of Kodaikanal and Madras Observatories to Pirojshaw H Daste. He states that the sun does not enter the constellation of Aries on March 21; it is called the sign of Aries on or about the date, and this entry coincides with the spring equinox. The date of entry into the constellation Aries slowly changes.

This is a Letter from Pirojshaw H Dasteer to the Director of Kodaikanal and Madras Observatories regarding the sun's entry into Aries. Through this query, he asks 2 main questions: which zodiac was the sun when he entered it, and when and at what time does the sun really enter the first star of the Aries?

This letter was sent from the Astronomer Royal, Royal Observatory, Greenwich, F. W. Dyson, to John Evershed confirming that no photographs would be taken at Kodaikanal from July 1, 1915, until further notice.

The letter is from the Director General of Observatories to Charles Michie Smith regarding disturbances in the mines of Mysore, which they term as 'Air blast, enclosing a list of when it happened in August and September, asking to see if any earthquakes were recorded in Kodaikanal and send the remarks.