Professor Asa Gray well said, "For the telegraph and for electro-magnetic machines, what was now wanted was not discovery, but invention; not the ascertainment of principles, but the devising of methods." Morse is not to be less honored because somebody discovered the principle, which he and others utilized for the race, any more than Edison, Bell, and others, because Faraday and Henry helped to make their grand work possible. "My next investigation, after being settled at Princeton," says Professor Henry, "was in relation to electro-dynamic induction. Mr. Faraday had discovered that when a current of galvanic electricity was passed through a wire from a battery, a current in an opposite direction was induced in a wire arranged parallel to this conductor. I discovered that an induction of a similar kind took place in the primary conducting wire itself, so that a current which, in its passage through a short wire conductor, would neither produce sparks nor shocks would, if the wire were sufficiently long, produce both those phenomena.... "A series of investigations was afterwards made, resulting in producing inductive currents of different orders, having different directions, made up of waves alternately in opposite directions.... "Another series of investigations, of a parallel character, was made in regard to ordinary or frictional electricity. In the course of these it was shown that electro-dynamic inductive action of ordinary electricity was of a peculiar character, and that effects could be produced by it at a remarkable distance. For example, if a shock were sent through a wire on the outside of a building, electrical effects could be exhibited in a parallel wire within the building."... After this, investigations were made in atmospheric induction; induction from thunder clouds; in regard to lightning rods; on substances capable of exhibiting phosphorescence, such as the diamond, which, when exposed to the direct rays of the sun, and then removed to a dark place, emits a pale blue light; on a method of determining the velocity of projectiles; on the heat of the spots on the sun as compared with the rest of his disk; the detection of heat by the thermal telescope--"when the object was a horse in a distant field, the radiant heat from the animal was distinctly perceptible at a distance of at least several hundred yards;" on the cohesion of liquids; on the tenacity of soapwater in films; on the origin of mechanical power, and the nature of vital force. Henry says:--