The letter was written by Houghtons Ltd. to The Secretary of State for India in Council on the enquiry about the quality of the spectrograph slides being sent to Kodaikanal Observatory.

This letter was about M. K. Vainu Bappu's performance and his stay in Harvard College during his Ph.D. and he also received commendations from his guides, seniors and colleagues.

This fond includes an introduction exploring the Sun's significance in relation to life and activities on Earth. Additionally, it comprises five chapters covering topics such as the distance and dimensions of the Sun, methods and apparatus for studying the Sun's surface, the spectroscope and solar spectrum, and an examination of sunspots. The book is part of International Scientific Series, Vol. XXXIX

The Recent Progress of Astronomy: Especially in the United States was a book by Elias Loomis and published in 1856. It was about the history of astronomy, providing valuable information about the advancements and discoveries in the field during the early nineteenth century. It has 502 pages.

This letter was about the Bappu's application for admission into Harvard Observatory and the formalities discussed by Harlow Shapley.