14 April 1857
I wish I had Known You were going to Paris, I would have troubled You with a small packet which I am sure you could have taken charge of for me: Your observations on the patent laws appear to me judicious and well founded. With respect to Mr Archer <1> if he had patented his collodion process, early enough, the result would probably have been that he would have acquired a large fortune by it, but on the other hand he would have lost the credit which he now has, or ought to have, of having presented the invention gratuitously to the Public. So that there is something to be said on both sides of the question.
1. The wet collodion on glass negative process was given freely to the public in 1851 by Frederick Scott Archer (1813-1857), a sculptor and photographer. He disclosed the operational details in an 18 February 1851 letter published in The Chemist, n.s. v. 2 no. 19, March 1851, pp. 257-258.