It appears that Mr. Day, “the sole projector of the scheme, and as matters have turned out, the unhappy sacrifice to his own ingenuity,” planned a method of sinking a vessel under water with a man in it, who should live there for a certain time, and then by his own means only bring himself up to the surface. He tried his project in the Broads near Yarmouth, fitting a Norfolk market-boat for his purpose, and succeeded in sinking himself thirty feet under water, where he continued during the space of twenty-four hours. Elated with this success, he then wanted to avail himself of his invention. He conversed with his friends, perfectly convinced that he had brought his undertaking to a certainty; but how to reap the advantage of it was the difficulty that remained. [Illustration: THE “INTELLIGENT WHALE” OF HALSTEAD. (1892.) ] That this vessel might serve some useful purpose, whether peaceful or warlike, does not seem to have occurred to Mr. Day, who was content seemingly to construct a diving boat capable of sinking and rising again to the surface, without furnishing it with any method of propulsion. A friend of the inventor suggested that if he acquainted the sporting gentlemen with the discovery and the certainty of the performance considerable “betts” would take place as soon as the project should be mentioned in Company. Struck by this happy idea, Mr. Day looked into the “Sporting Kalendar” and finding therein the name of Blake decided that it was to this gentleman that he ought to address himself. Accordingly, in November, 1773, Mr. Blake received the following letter:— “SIR,—I have found out an affair by which many thousands may be won. It is of a paradoxical nature, but can be performed with ease; therefore, sir, if you chuse to be informed of it, and give me £100 for every £1,000 you shall win by it, I will very readily wait upon you, and inform you of it. I am, myself, but a poor mechanic and not able to make anything of it without your assistance. “Yours, &c., “J. DAY.” Mr. Blake naturally had no conception of Mr. Day’s design, nor was he sure that the letter was serious. He wrote, however, to the inventor, and appointed an interview, when the latter announced his project. He declared “that he could sink a ship one hundred yards deep in the sea with himself in it, and remain therein for the space of twenty-four hours, without communication with anything above; and at the expiration of the time rise up again in the vessel.”