They were used in Washington as well as the type for numerals in the winter of 1837-38.
"In the earlier period of the invention it was a matter which experience alone could determine whether the _numerical_ system, by means of a numbered dictionary, or the alphabetic mode, by spelling of the words, was the better.

While I perceived some advantages in the alphabetic system, especially in the writing of proper names, I at that time leaned rather towards the _numerical_ mode under the impression that it would, on the whole, be the more rapid.

A very short experience, however, showed the superiority of the alphabetic mode, and the big leaves of the numbered dictionary, which cost me a world of labor, and which you, perhaps, remember, were discarded and the alphabetic installed in its stead." Perhaps the most conclusive evidence that Vail did not invent this alphabet is contained in his own book on the "American Electro-Magnetic Telegraph," published in 1845, in which he lays claim to certain improvements.

After describing the dot-and-dash alphabet, he says:-- "This conventional alphabet was originated on board the packet Sully by Professor Morse, the very first elements of the invention, and arose from the necessity of the case; the motion produced by the magnet being limited to a single action.

During the period of the thirteen years _many plans have been devised by the inventor_ to bring the telegraphic alphabet to its simplest form." The italics are mine, for the advocates of Vail have always quoted the first sentence only, and have said that the word "originated" implies that, while Vail admitted that the embryo of the alphabet--the dots and dashes to represent numbers only--was conceived on the Sully, he did not admit that the alphabetical code was Morse's.