The letter was a request for sending copies of all printed forms, instructions, and full particulars of the photographic process in connection with the 8-inch solar photographs done by the Superintendent of Trigonometrical Survey.

The letter was written by E. C. J. Bond, the officer in charge No. 18 party (Magnetic), Survey of India, to the Director of the Solar Physics Observatory, Kodaikanal. E. C. J. Bond has mentioned some suggestions to the magnetic observers to get accurate values during the observations. It was written in 1920 in Dehra Dun.