Harley Street <1>
May 22 21/54.
My dear Sir
I cannot have the smallest objection to state (and I think I very clearly expressed myself to that effect in my letter) that I believe the developement of the latent image by Gallic acid (whether it occurs in the Collodion or any other process) in iodised Silver, was your invention and as you express it in the three points put in your note just received – was
1st was a leading feature of the Kalotype process, <2>
2d was new
3d was of great importance to photography
It is only as respects the Collodion process that I demurred and really if your defendant <3> sets up a plea that he does not employ your process but another it is he who is bound to describe that other process and shew that yours is not part and parcel of it. He might have set up a general denial and simply pleaded that he did not employ your process. Surely he would have been put on proof that what he did employ was a different one from yours.
A makes Photographs for sale<.> B prosecutes him (of course on some primâ facie evidence of the facts) for infringement of patent, asserting that he uses his process.
A denies that he does so & asserts that he uses another, naming one of which there exist printed and published descriptions of a very circumstantial kind.
Surely these descriptions can be appealed to with far more effect than the belief of C, D, E, &c, to shew that the process so named involves B’s patented principle – & that principle once established carries with it this specific application.
Believe me yours vy ty
JFW Herschel
H. F. Talbot Esqr &c
[draft letter in Herschel’s hand:]
May 21/54
My dear Sir
I cannot have the smallest objection to state (and I think I very clearly expressed myself to that effect in my letter) that I believe the developement of the latent image by Gallic acid (whether it occurs in the Collodion or any other process) in iodised silver was your invention – and as you express it in the three points put in your note just received – was
1. was a leading feature of the Kalotype process
2. was new
3. was of great importance to Photography.
It is only as respects the “Collodion process” that I demurred and really if your defendant sets up a plea that he does not employ your process but another viz: one to which he gives a name – it is he who is bound to describe that other process and shew that yours is not part & parcel of it. He might have set up a general denial – and simply pleaded that he did not employ your process but a different one . Surely he would have been put on proof that it was a different one from yours.
A makes photographs for sale B prosecutes him of course on some primâ facie evidence of the facts for infringement of patent asserting that he uses his process
A denies that he does so & asserts that he uses another, naming one of which there exist printed and published descriptions of a very circumstantial kind
Surely these descriptions can be appealed to with far more effect than the belief of C,D,E, &c to shew that the process so named involves B’s patented principle – & that principle once established carries with it this specific application.
Believe me yours vy ty
JFW Herschel
Notes:
1. London.
2. Herschel often used this variant spelling for calotype.
3. James Henderson, photographer, London.