On the Rapid Production of Steam. 293 



The flue being placed eccentric, with respect to the main cylinder 

 of the boiler, and indeed wholly below its center, will be entirely 

 immersed when the boiler is half filled with water. The furnace be- 

 ing at one end, the flame passes along the whole length of the boil- 

 er on the outside, and then entering the flue returns to a chimney- 

 near the upper or fire end. The boilers are all connected together 

 by a pipe forming a water communication at bottom, and by anoth- 

 er, forming a common steam passage above their upper surfaces. 

 The lower gauge cock is placed from one to three inches above the 

 top of the flue; and so long as the deck remains perfectly horizon- 

 tal, and the forcing pump for injecting water performs its office, a 

 moderate degree of care, on the part of firemen and engineers, may 

 insure the complete immersion o( the flue. But when from any 

 cause, the boat inclines to either side, there will be a transfer of wa- 

 ter through the lower connecting pipe from the boilers on the eleva- 

 ted, to those on the depressed side of the deck. A large number 

 of passengers collecting on one side would doubtless be sufficient to 

 cause a " heeling" of a foot or more, and this would lay bare the 

 whole of the flue in the upper boiler, and expose more or less sur- 

 face of iron in every flue and boiler on the elevated side. Every 

 pound of water thus transferred, serves to increase by double its own 

 weight, the tendency of the boat to careen, and even after the other 

 causes of unequal depression have ceased to act, the water thus dis- 

 placed will continue its influence, and will not until after sometime, 

 return to its former level through the pipe of communication. The 

 removal of water from the part of the usual generating surface of 

 metal, will cause the supply oi steam to be diminished, so that the 

 engine may appear to labor, even while the boiler is becoming red 

 hot. This circumstance, is known to have preceded some of the 

 most frightful explosions, and it is but the natural result of employ- 

 ing that caloric which ought to be producing steam, in merely rais- 

 ing the temperature of metal, with the incidental effects of heating 

 the steam already generated, considerably above the temperature 

 which belong to its actual density. Not only must those parts of the 

 boilers and flues which are immediately exposed to the fire, become 

 unduly heated, but, owing to the high conducting power of the me- 

 tal, the upper arch of the cylinder, as well as the lower, will rapidly 



temperature 



Some may pos- 



sibly imagine that since the engine moves slowly for a time in conse- 

 quence of a deficiency of generating surface, it will only move with 

 Vol. XIX.— No. 2. 38 



