JOHN ERICSSON. 379 



which afterward came into general use on our river steamers; 

 in 1834 he took out a patent for a deep-sea lead, on a prin- 

 ciple similar to the one employed in a lead designed by Sir 

 William Thomson. He received a prize from the London 

 Society of Arts for a hydrostatic weighing machine. He ex- 

 hibited at the International Exhibition in 1852, and received a 

 medal for them, an instrument to measure distances at sea ; an 

 alarm barometer which sounded a gong in warning of approach- 

 ing storms; and a pyrometer which measured temperatures up 

 to the boiling point of iron. He invented an instrument for 

 measuring the compressibility of water; methods of propelling 

 boats on canals, one of which has been applied to the heavy 

 grades of Swiss mountain railroads ; a water meter, a centrif- 

 ugal pump, a file-cutting machine, an apparatus for making 

 salt from brine, and numerous applications to the steam engine, 

 many of which came into use, while others were abandoned. 

 He experimented with superheated steam; and Mr. Church 

 says that he designed more than five hundred steam engines. 



While he was making all these machines he was also experi- 

 menting with designs for a caloric engine. His researches in 

 this direction were begun with the " flame engine " already 

 mentioned. He contributed a paper on the subject to the 

 English Institution of Civil Engineers in 1826; built three en- 

 gines in 1827 based on the principle of the expansion of air; 

 brought out a completed caloric engine in 1833, to which he 

 applied improvements as his investigations continued ; received 

 the Rumford medal in 1856 for his researches into the nature 

 of heat ; and, according to Mr. Church, spent in thirty years, 

 including the engines for his caloric ship, more than a quarter of 

 a million of dollars in building twenty-seven experimental en- 

 gines. The caloric system was not successful when applied to 

 the propulsion of large vessels like the Ericsson, although 

 that vessel registered a speed of eight and attained at one 

 time a speed of eleven miles an hour, but for lighter work it 

 has proved very practicable and efficient ; the smaller machines 

 have been extensively used, and the inventor derived large 

 profits from them. 



The first experiment with the screw propeller was made in 

 1836 by Captain Ericsson, in conjunction with his friend Francis 

 B. Ogden, of New Jersey, United States consul at Liverpool. 

 A model of the apparatus was built and tested in a public bath. 



