recognition of his service the Spanish Government conferred upon Ericsson the decoration of Isabel la Católica.
Captain Ericsson's ideas of a war vessel for submarine work more seaworthy than the monitors were embodied in the Destroyer, which was launched in 1878. “It is an iron vessel, one hundred and thirty feet long, seventeen feet wide, and eleven feet deep, protected by a wrought-iron breastwork of great strength near the bow,” carrying a submarine sixteen-inch gun thirty feet long, the muzzle of which projects through an opening in the stem near the bottom, and which is intended to carry a fifteen-hundred-pound projectile charged with three hundred pounds of guncotton. The vessel is intended to attack “bow on,” and to discharge its projectile from within three hundred feet of the object of assault. The bill for the purchase of this vessel by the United States, although it passed the Senate in 1885, failed to become a law.
“Three distinct purposes,” says Mr. Church, “are apparent in Ericsson's labors: first, to improve the steam engine and extend the scope of its application; next to discover some more economical and efficient method for changing the mode of motion we call heat into the mode of motion we call power; third, to force the great maritime nations to declare the ocean neutral ground, by making naval warfare too destructive a pastime to be indulged in.” We have seen how he worked out the first of these ideas in his numerous adaptations of the steam engine, and the third in the monitors and the Destroyer. In trying to make the second idea practical he devised the caloric engine and devoted many of the later years of his life to the investigation of the solar heat and of methods of converting it into a direct source of mechanical power. He devised and constructed a solar engine in 1883, which was described and illustrated in Nature (Vol. XXIX, p. 217), and labored until within two years of his death to improve and perfect it. In his description of this engine he showed that with reflecting plates of one hundred and thirty by one hundred and eighty inches and a steam cylinder of six by eight inches he could obtain a speed of engine of one hundred and twenty turns per minute, with an absolute pressure on the working piston of thirty-five pounds per square inch. He devoted himself regularly and, except for the daily walk for his health, unremittingly to his work. Fitting up his office and workshop in Beach Street, New York, he occupied his whole time in investigation, experiment, and construction, refusing to be interrupted, and shutting himself out from general visitors. He was a man of great physical strength, and some remarkable stories are told of his feats in lifting. In one of them, when in youth he raised a weight of six hundred pounds, he thought he overstrained himself, and