PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 375 



The inclination of Bergen Hill was stated by some persons 

 present to be 1 in 15. There were long beds of broken stone on 

 it,' which common carriages avoided, keeping on the rail track; 

 and the carriage ran up over these beds, thus proving a tractive 

 force sufficient for ordinary purposes. On a level, on a bed of 

 stone, we were running very fast — some thought more than 20 

 miles per hour — when the exhaust was so rapid as to tear open 

 soldered joint of the chamber of copper one-fiftieth of an inch 

 thick, an accident that arose from the economy of using an old 

 water-tank as material for the exhaust chamber. This left us 

 without the steam blast, notmthstanding which we returned, 

 about a mile, at a speed equal to an omnibus, having seventy 

 pounds pressure when we arrived at the locomotive works. 



It is the opinion of Mr. Davis, superintendent of the works, 

 that the engines are well-proportioned to the weight, and that 

 there is boiler surface enough for much greater speed than is 

 required ; in fact, we ran over beds of stone faster than we shall 

 be allowed to run on smooth roads when carrying passengers, 

 and this speed was attained with the door wide open, and the 

 boiler, pipes and .cylinders naked. When these parts are clothed, 

 and the blast-pipe adjusted, I believe there will be abundance of 

 steam, with very little back pressure. 



Comparing this performance with that of Ogle's and Mace- 

 rone's carriages, which were of about equal weight, we see abund- 

 ant encouragement. Their boilers had 250 feet of surface, mine 

 has 159 feet; they ran on better roads, and yet seldom attained 

 so high a speed. Their boilers vaporized about five pounds of 

 water per foot surface per hour, and mine — which is the vertical 

 tubular boiler — appears to steam as fast as the best locomotive 

 boilers, which vaporize fifteen pounds per foot per hour. Add 

 to this the advantages of the link, and we see that the improve- 

 ments that have grown up since their time, place us in a position 

 so favorable as to compensate for the inferior quality of our 

 roads. And further, the cost of this improved machinery is less 

 than half what they had to pay for theirs. 



Besides these improvements which 1 adopt from the locomo- 

 tive, I claim that my parallel connection is important, not only to 

 preserve the carriage from damage by jolting, but aslo to diminish 

 the resistance. Morin found that at nine miles per hour a car- 

 riage with common springs ran with half the power it required 

 when its springs were blocked ; and my connection enables me 



