This letter was about the spectroheliograph, observations of widened lines in Sunspot spectra and prominence latitudes and frequencies.

This letter was about a drawing of the spectroheliograph that was received at Gilbert T. Walker from the Cambridge Scientific Instrument Company.

This letter was about the continuation of the delayed telegram of 30th May 1905. It also contains the recommendation of the observatories committee & relating to spectroheliographic work.

The letter is from Gilbert T. Walker, Director General of Observatories, to The Secretary to the Government of Madras, P.W.D, Madras, reporting that no works on which expenditure is imperial and not less than Rs.2500/- will be required during the ensuing year. And requested funds from 1917-18 for the special repairs of the roof of the spectroheliograph building.

The letter is from Gilbert T. Walker, Director General of Observatories to The Secretary to the Government of Madras, P.W.D, Madras, forwarding duly approved and countersigned plan and estimate of Rs. 2340/- for special repairs to the roof of the spectroheliograph building at Kodaikanal. Also adding, if it's not convenient to provide the funds during 1916-17, the work may be carried out in the year 1917-18 before cold weather.

The letter is from Gilbert T. Walker to Charles Michie Smith regarding reproducing spectroheliograms at home. It states that a sanction would be required from the government and suggests including as many firms as possible with the approximate cost.

The letter is from the Executive Engineer to John Evershed informing that no intimation has been received that the funds required for the spectroheliograph building have been placed at his disposal and, hence, regretting that he can't start the work.

The letter is from the Executive Engineer Madura division to the Superintending Engineer VI circle Trichinopoly. It is regarding the work of the spectroheliograph building, requesting to comply with the indent for iron articles as no further progress can be made without it.

The letter is from the Director, Kodaikanal & Madras Observatories to the Executive Engineer, Madura, mentioning Mr R. Savarinathan, about making a watertight roof and also not signing the estimate as it does not provide for working without interfering in the use of instruments.

Charles P. Butler sent this letter to Gilbert T. Walker on installing a spectroheliograph in the Kodaikanal Observatory. The letter was sent from the Royal College of Science, London, on 3rd June 1904.