Fig. 10. 



STEAM NAVIGATION. 



CHAPTEE III. 



45. Economy of fuel. 46. Width and depth of furnace. 47. Advantage 

 of expansive action. 48. Siamese engines. 49. Simplified arrange- 

 ments. 50. Number and position of cylinders. 51. Proportion of 

 diameter to stroke. 52. Oscillating engines. 53. Engines of the 

 Peterhoff. 54. Propellers. 55. The common paddle-wheels. 56. 

 Feathering paddles. 57. Morgan's paddle-wheel. 58. Field's split 

 paddles. 59. American paddle-wheel. 60. Practical objections to 

 feathering paddles. 61. Proportion of marine engines. 62. Sub- 

 merged propellers. 63. Their disadvantages. 64. Screw-propellers. 

 65. Pitch and slip. 66. Manner of mounting screw-propellers. 

 67. Their various forms. 



45. XHE economy of fuel depends in a great degree on the 

 arrangement of the furnaces, and the method of feeding them. 

 In general, each boiler is worked by two or more furnaces 

 communicating with the same system of flues. "While the furnace 

 LARDNER'S MUSEUM OF SCIENCE, L 145 



No. 126. 



