Besides the enormous engineering difficulties of producing a cable long enough and strong enough, and laying it at the bottom of the Atlantic, there were electrical problems involved far greater than Morse seems to have realized. It had been discovered that the passage of a current through a submarine cable is seriously retarded. The retarding of the current as it passes through the water is a difficulty that does not exist with the land telegraph stretched on poles. Faraday had demonstrated that this retarding was caused by induction between the electricity in the wire and the water about the cable. The passage of the current through the wire induces currents in the water, and these moving in the opposite direction act as a drag on the passage of the message through the wire. What the effect of this phenomenon would be on a cable long enough to cross the Atlantic wan a serious problem that required deep study by the company's engineers. It seemed entirely possible that the messages would move so slowly that the operation of the cable, once it was laid, would not pay. Faraday failed to give any definite information on the subject, but Professor William Thomson worked out the law of retardation accurately and furnished to the cable-builders the accurate information which was required. Doctor Whitehouse, electrician for the Atlantic Company, conducted some experiments of his own and questioned the accuracy of Thomson's statements. Thomson maintained his position so ably, and proved himself so thoroughly a master of the subject that Field and his associates decided to enlist him in the enterprise. This addition to the forces was one of the utmost importance. William Thomson, later to become Lord Kelvin, was probably the ablest scientist of his generation, and was destined to prove his great abilities in his early work with the Atlantic cable. William Thomson was born in Belfast, Ireland, in 1824. His father was a teacher and took an especially keen interest in the affairs of his boys because their mother had died while William was very young. When William was eight years of age his father removed to Glasgow, Scotland, where he had secured the chair of mathematics in Glasgow University. His early education he secured from his father, and this training, coupled with his natural brilliancy, enabled him to develop genuine precocity. At the age of eight he attended his father's university lectures as a visitor, and it is reported that on one occasion he answered his father's questions when all of the class had failed. At the age of ten he entered the university, together with his brother James, who was but two years older. The brothers displayed marked interest in science and invention, eagerly pursued their studies in these branches, and performed many electrical experiments together. [Illustration: CYRUS W. FIELD] [Illustration: WILLIAM THOMSON (LORD KELVIN)]