CATALOGUE OF THE WATERCEAFT COLLECTION. 53 



Isle of Wight in 1851. When in England in 1805 he went to Heath- 

 field, the seat of Watt, who had then retired from business, and pre- 

 sented a letter from his father. Watt received him kindly, but reit- 

 erated his well-known objections to the use of steam at a pressure 

 over two or three pounds above the atmosphere. These boilers of 

 Colonel Stevens have often been referred to in relation to the intro- 

 duction of the multitubular boiler on locomotives. 



At the date of the introduction into use of the screw propeller, 

 the pressure of steam carried on the boilers of condensing engines of 

 the vessels that now navigate the bays and rivers of the Atlantic 

 seaboard averaged about 10 pounds to the square inch, while on the 



FIG. 8. JOHN STEVENS' STEAMBOAT BOILER AND ENGINE. 



innumerable steamboats on the Mississippi and its tributaries the 

 steam averaged 140 pounds to the square inch. At the same date, the 

 pressure on English vessels was the same that Watt had established — 

 namely, 2| to 3 pounds. The Great Western, in 1828, carried that 

 pressure, and the iron screw propeller Great Britain., in 1840, car- 

 ried only 5 pounds to the square inch. 



Colonel Stevens attempted to introduce steam navigation by the 

 screw propeller, laboring at the project for six years, and relinquish- 

 ing it only one year before the successful application of the paddle 

 wheel by Fulton.^ The five distinct means he proposed were : 



First. The short, four-bladed screw propeller. 



Second. The use of steam of high pressure. 



Third. The multitubular boiler. 



■ Tlie original drawing of tlie machinery of the Clermont made by the hand of Fulton 

 forms a part of the exhibition series in the section of naval architecture in the United 

 States National Museum. 



