to the end of a wire half a mile in length, but as yet there was no means of receiving them back again from the other extremity. He continued to experiment on his invention, and made several improvements in it. It was plain from the first that he needed a duplicate of his instrument at the other end of his wire, but he was unable for a long time to have one made. At length he acquired the necessary funds, and in July, 1837, had a duplicate instrument constructed, and thus perfected his plan. His telegraph now worked to his entire satisfaction, and he could easily send his signals to the remote end of his line and receive replies in return, and answer signals sent from that terminus. Having brought it to a successful completion, he exhibited it to large audiences at the University of New York, in September, 1837. In October, 1837, Professor Morse filed a caveat to secure his invention, but his patent was not obtained until 1840.
He now entered upon that period of the inventor's life which has proved so disastrous to many, and so wearying and disheartening to all—the effort to bring his invention into general use. It was