In answer to your note of yesterday the two spectra which you so kindly lent for exhibition at our Soirée are at present in the hands of Captain [William de Wiveleslie] Abney. I have just written to Captain Abney to ask him to return them to you without delay. The spectra excited great interest among our Fellows and visitors.
I am, yours sincerely,
Asst. Sec. R.S. [Assistant Secretary, Royal Society]'.