To De Corny
Paris Dec. 17. 1787.
It is time to give you an account of your copying machine, which, after repeated trial, I find very inadequate to it’s offices. Instead of having two rollers only, thus placed, where the pressure of the upper roller is resisted in the same points by the lower one, and so forces the copy extremely, it is made with one roller above and two below, thus so that at the point where the upper roller presses, there is a void below, which permits the sliding board to bend and withdraw itself from the pressure. The lower rollers are also very small and of wood, so that they bend. The springs are of wire rolled spirally like a bell wire, and do not perform their office as well as steel springs by any means. I have shewn it to a very excellent mechanic who has made several for persons here by my order. He agrees that the good materials of this will save half the expence of the machine, and he will ask 5. Louis for making those which must be changed. The machine would then be perfect and worth nine or ten guineas. I told him I would communicate to you the result of our consultation, and you will decide for yourself. I have the honour to be with sentiments of great esteem and respect Sir Your most obedient & most humble servt.,