This letter was reply to C. M. Smith towards the heating employed in transit room and spectrograph room. Gilbert T. Walker's expressed his openion on heating of both the room in detail.

The letter is from John Evershed to Messrs Adam Hilger regarding an order for three 60-degree flint prisms of the highest defining quality, two pieces of plane glass highest quality surfaces with one side polished, two pieces of plane parallel blue or green glass of good optical quality transmitting blue light but absorbing violet and ultra-violet. The letter mentions that the bill should be sent to the Director General of Observations in Simla, India.