H.M.S. Agamemnon laying the Atlantic cable in 1858. A whale crosses the line.
"ÍThe construction of the first Atlantic cable differed materially from earlier cables. Its central conductor was stranded , consisting of seven pure copper wires, laid together to form a single conductor. It was covered with three layers of gutta percha to a diameter of nearly 12.2 mm. This core was then covered with a thin layer of hemp and yarn and it was armoured with 18 seven-wire strands of thin iron wire. A total of 3200 kilometers of this cable was made, and stowed aboard H.M.S. Agamemnon, a jury-rigged and screw-driven wooden British warship. Paying out started on 7 August, 1857, from Valentia on the west coast of Ireland. On 17 August the cable broke in 2000 fathoms of water, and the project was abandoned for the year.
"A different plan was adopted for next year's attempt. H.M.S. Agamemnonand U.S.N.S. Niagara, each loaded with a suitable length of cable, met in mid-ocean, and proceeded to pay out the spliced cable towards their respective home ports. On 28 June, the third splice having proved successful, both ships started from their meeting place, but after only 230 kilometers the cable snapped on the Agamemnon. Both ships then proceeded to Queenstown in Newfoundland to receive their new orders from the directors of the Company.
"It was decided to repeat the attempt and on midnight, 28 July, 1858, the two vessels once more met in mid-ocean, spliced their cables and started out in opposite directions. On 5 August, a total of 3240 km had been laid, the Agamemnon now anchored in Dowlas Bay, Valentia, Ireland and the Niagara anchored in Trinity Bay, Newfoundland. At 2.45 a.m. of that day the first telegraphic message passed across the Atlantic Ocean. It merely announced to the Niagara that the Agamemnon had landed the cable." (From Semaphore to Satellite, Published by the International Telecommunication Union, Geneva 1965)