EDGEWORTHTOWN, Dec. 11, 1794. I have been employed for two months in experiments upon a telegraph of my own invention. I tried it partially twenty-six years ago. It differs from the French in distinctness and expedition, as the intelligence is not conveyed alphabetically.... I intended to detail my telegraphs (in the plural), but I find that I have not room at present. If you think it worth while, you shall have the whole scheme before you, which I know you will improve for me. Suffice it, that by day, at eighteen or twenty miles' distance, I show, by four pointers, isosceles triangles, twenty feet high, on four imaginary circles, eight imaginary points, which correspond with the figures 0, 1, 2, 3, 4, 5, 6, 7. So that seven thousand different combinations are formed, of four figures each, which refer to a dictionary of words that are referred to,--of lists of the navy, army, militia, lords, commons, geographical and technical terms, &c, besides an alphabet. So that everything one wishes may be transmitted with expedition. By night, white lights are used. _Dr. Darwin to Mr. Edgeworth._ DERBY, March 15, 1795. DEAR SIR,--I beg your pardon for not immediately answering your last favor, which was owing to the great influence the evil demon has at present in all affairs on this earth. That is, I lost your letter, and have in vain looked over some scores of papers, and cannot find it. Secondly, having lost your letter, I daily hoped to find it again--without success. The telegraph you described I dare say would answer the purpose. It would be like a giant wielding his long arms and talking with his fingers; and those long arms might be covered with lamps in the night. You would place four or six such gigantic figures in a line, so that they should spell a whole word at once; and other such figures in sight of each other, all round the coast of Ireland; and thus fortify yourselves, instead of Friar Bacon's wall of brass round England, with the brazen head, which spoke, "Time is! Time was! Time is past!" MR. EDGEWORTH'S MACHINE. Having slightly mentioned the contrivances made use of by the ancients for conveying intelligence swiftly, and having pointed out some of the various important uses to which this art may be applied, I shall endeavor to give a clear view of my attempts on this subject.