United States or Andorra ? Vote for the TOP Country of the Week !
A. It has not been applied to the vessels themselves, as in the case of screw vessels, but it has been employed on shore to ascertain the amount of tractive force that a paddle vessel can exert on a rope. Q. Have any experiments been made to determine the comparative performances of screw and paddle vessels at sea?
"Do we not see civilization," asks the author, "advancing along those lines where the tractive forces are the greatest, where the least labor will produce the largest crops, and where the obstacles to complete living are the fewest? Do not people invest their money where it will safely bring the largest returns? Do we not buy in the cheapest, and sell in the dearest market?
The boiler pressure is 140 lb., and the tractive force per pound of mean cylinder pressure 106 lb.; the total wheel base is 14 ft. 6 in. The boiler is 10 ft. 2 in. long and 4 ft. 4 in. diameter, and the heating surface is in the tubes, 858 square feet; fire-box, 90 square feet; total, 948 square feet.
A locomotive depends for its tractive power on its weight pressing on its driving wheels, and the more driving wheels there are and the heavier the locomotive, the more it can pull, though in that case speed is lost. This is why freight locomotives are so heavy and have so many large driving wheels. They pull the engine along, and the cars also, by their weight pressing on the rails.
I was not at that time aware that George Stephenson and others had adopted the same method; but it was afterwards gratifying to me to find that I had been correct as regards the important uses of the steam blast in the chimney. In fact, it is to this use of the waste steam that we owe the practical success of the locomotive-engine as a tractive power on railways, especially at high speeds.
The boiler is 11 ft. 6 in. long and 3 ft. 11 in. diameter, and the grate area is 17 square feet. The heating surface is in the tubes 1,057 square feet; fire-box, 87 square feet; total, 1,144 square feet. The tractive force per pound of mean cylinder pressure is 88.4 lb.
Miriam burst out laughing. "Mike," she cried, "nobody is going to get married here." Mike's eyes glistened. "That so, sure?" he said. "You see, Miss Miriam, you an' your brother is both so 'tractive, that I sort o' 'sposed you might be thinkin' of gittin' married, an' if that was so, I couldn't go to Seraphina, an' git her to come here when things wasn't fixed an' settled."
The boiler pressure is 140 lb., and the tractive power per lb. of mean cylinder pressure 92 lb. The total wheel base is 17 ft. 6 in. The boiler, which is fed by two injectors, is of steel, 11 ft. 5 in. long and 4 ft. 2 in. diameter. The grate area is 17.3 square feet, and the heating surface is, in the tubes, 1,083; fire-box, 117; total, 1,200 sq. ft.
He points out that horses involve a large original investment, are worn out in farm work, and after their prime steadily depreciate in value; while, on the other hand, the ox can be fattened for market when his usefulness as a draught animal is over, and then sell for more than his original cost; that he is less subject to infirmities than the horse; can be fed per tractive unit more economically and gives more valuable manure.
At slight speeds, and up to 19.5 kilometers per hour, the Gitana, which is the sharper, runs easier and requires a slighter tractive stress. At such a speed there is an equality; but, beyond this, the Pictet boat presents the greater advantages, and, at a speed of 27 kilometers, requires a stress about half less than does the Gitana.
Word Of The Day