This correspondence is related to half yearly return of Instruments at the Periyakulam Observatory which were in use on 31st March 1900

The fond contain correspondence of the annual reports of scientific works at Kodaikanal

The fond contain correspondence between the Executive Engineer, Superintending Engineer, Director of Kodaikanal & Madras Observatories, and the Director General of Observatories regarding various constructions and alterations in the Kodaikanal Observatory building.

This fond contains correspondences related to time signals

The fond contains correspondence regarding the water pump and pump house in Kodaikanal.

This fond contains letters and documents related to the meteorology in Kodaikanal during 1898 to 1925

This font is regarding Instruments used in Kodaikanal Observatory

This fond contains correspondences related to clocks in Madras and Kodaikanal Observatory

This fond contains official letters related to William Butler from March to November 1908.

This fond contains letters, annual expenditure reports and bills of Kodaikanal and Madras Observatories. It also contains correspondence of John Eliot,Charles Michie Smith and R.E.V.Arbuthnot during July 1901 to March 1903 regarding the index slip, meteorological summaries, seismological reviews and disturbances and other reports like annual expenditure, bills, and telegraphs. It has a report on the condition and proceedings of the government observatory, Colaba, written by N.A.F.Moos. It also has letters from the Royal Society of India, H. Grubb, J. Larmer, R. Fuess, William Butler and Charles P. Butler to the Meteorological Department and Kodaikanal & Madras Observatory.