Letter to Richard Guy Ash about a dicyanine experiment
My dear Ash
I'll be home on Wednesday. I shall be very interested to hear from you — or to see you on Thursday — and learn where we are now in our dicyanine experiment. I don't know if you have done anything. The great thing would seem to be to have two slightly concave slides & imprison the dicyanine between them. What he means by the 'light' screen as distinguished from the dark are I don't know.
- Yours sincerely
- A Conan Doyle
Order anything you wish & put it down to me.
- Source: Brian Pugh Collection.