Furthermore Professor Henry, with the clear vision of a trained mind, points out that advances in discovery and invention are necessarily slow and dependent upon the labors of many in the same field.
His cordial endorsement of the invention, in this letter and later, so pleased and encouraged Morse that he refers to it several times in his correspondence.

To Mr.Smith, on July 16, 1842, he writes:-- "Professor Henry visited me a day or two ago; he knew the principles of the Telegraph, but had never before seen it.

He told a gentleman, who mentioned it again to me, that without exception it was the most beautiful and ingenious instrument he had ever seen.

He says mine is the only truly practicable plan.

He has been experimenting and making discoveries on celestial electricity, and he says that Wheatstone's and Steinheil's telegraphs must be so influenced in a highly electrical state of the atmosphere as at times to be useless, they using the deflection of the needle, while mine, from the use of the magnet, is not subject to this disturbing influence.