SKETCH OF JOHN ERICSSON. 119 



recognition of his service the Spanish Government conferred upon 

 Ericsson the decoration of Isabel la Catolica. 



Captain Ericsson's ideas of a war vessel for submarine work 

 more seaworthy than the monitors were embodied in the De- 

 stroyer, 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 be- 

 come 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 econom- 

 ical 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 de- 

 scribed 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 



