Dear Sir, It is many a day since I last had the pleasure of seeing and conversing with you, and, if I am not mistaken, it is as long since any communications have been exchanged.  However I trust it will not long be so.  When I last had the pleasure of seeing you it was when on my way to Philadelphia, at which time you had the kindness to show me specimens of the greatest discovery ever made, with the exception of the Electro-Magnetic Telegraph.  By the by, I have been thinking that it is time money in some way was made out of the Telegraph, and I am almost ready to order an instrument made, and to make the proposition to you to exhibit it here.  What do you think of the plan?  If Mr. Prosch will make me a first-rate, most perfect machine, and as speedily as possible, and will wait six or nine months for his pay, you may order one for me.

Morse’s reply to this letter has not been preserved, but he probably agreed to Vail’s proposition,—­anything honorable to keep the telegraph in the public eye,—­for, as we shall see, in a later letter he refers to the machines which Prosch was to make.  Before quoting from that letter, however, I shall give the following sentences from one to Baron Meyendorff, of March 18, 1840: 

“I have, since I returned to the United States, made several important improvements, which I regret my limited time will not permit me to describe or send you....  I have so changed the form of the apparatus, and condensed it into so small a compass, that you would scarcely know it for the same instrument which you saw in Paris.”

This and many other allusions, in the correspondence of those years, to Morse’s work in simplifying and perfecting his invention, some of which I have already noted, answer conclusively the claims of those who have said that all improvements were the work of other brains and hands.

On September 7, 1840, he writes again to Vail:—­

“Your letter of 28th ult. was received several days ago, but I have not had a moment’s time to give you a word in return.  I am tied hand and foot during the day endeavoring to realize something from the Daguerreotype portraits....  As to the Telegraph, I know not what to say.  The delay in finishing the apparatus on the part of Prosch is exceedingly tantalizing and vexatious.  He was to have finished them more than six months ago, and I have borne with his procrastination until I utterly despair of their being completed....  I suppose something might be done in Washington next session if I, or some of you, could go on, but I have expended so much time in vain, there and in Europe, that I feel almost discouraged from pressing it any further; only, however, from want of funds.  I have none myself, and I dislike to ask it of the rest of you.  You are all so scattered that there is no consultation, and I am under the necessity of attending to duties which will give me the means of living.

“The reason of its not being in operation is not the fault of the invention, nor is it my neglect.  My faith is not only unshaken in its eventual adoption throughout the world, but it is confirmed by every new discovery in the science of electricity.”