The failure of the pioneer cable has been attributed to a variety of causes, chief of which were defective construction and imperfect paying-out machinery, which produced unequal strains in the cable. Defective as the cable was at the moment of immersion, the various troubles became intensified with time, until at last, when provoked by the feebleness of the signals, the injudicious electrician at Valentia had recourse to the great penetrative power of the induction coil, and gave the dying cable the _coup de grâce_. An experiment made by Mr. Latimer Clark is not only germane to the subject, but is also of very great interest. Writing from Valentia on Sept. 12th, 1866, Mr. Latimer Clark says: "With a single galvanic cell, composed of a few drops of acid in a _silver thimble_[36] and a fragment of zinc, weighing a grain or two, conversation may easily, though slowly, be carried on through one of the cables (1865, 1866) or through the two joined together at Newfoundland; and although in the latter case, the spark, twice traversing the breadth of the Atlantic, has to pass through 3700 miles of cable, its effects at the receiving end are visible in the galvanometer in a little more than a second after contact is made with the battery. The deflections are not of a dubious character, but full and long, the spot of light traversing freely a space of 12 in. or 13 in. on the scale; and it is manifest that a battery many times smaller would suffice to produce similar effects." Not to be outdone by the English electrician, Mr. William Dickerson devised the gun-cap cell, which he used in 1866 with success in transmitting signals from Heart's Content, Newfoundland, to Valentia on the Irish coast. A piece of No. 16 bare copper wire was procured, one end of which was firmly twisted around the head of an empty _percussion-cap_. To one end of another similar length of wire was bound, with fine copper wire, a short strip of zinc bent at a right angle to form the anode element of the diminutive cell. After charging the cell with a drop of acidulated water of the size of an ordinary well-formed tear, and properly connecting the terminals with earth and cable, signals were transmitted over the cable by the infinitesimal current generated by this novel cell. The receiving operator reported that the signals were "awfully small"; but they were intelligible, and messages were successfully transmitted under the ocean by this tiny element. Contrast with this Lilliputian cell the enormous power that was used on the cable of 1858 toward the end of its short existence, when batteries of 380 and 420 Daniell cells were employed to force signals across.