894 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



American Institute, Polytechnic Association, 1 



Maij 14, ]8fi3. I 



Chairman, S. D. Tillman, Esq.; Secretary, Mr. John W. Chambers. 

 During the time devoted to ihiscellancous business the first subject pre- 

 Bented was 



Cannon. 



Mr. Rowell. — During the past week I have seen an account of some ex- 

 periments made at the English Naval Depot, at Woolwich, with guns, by 

 using balls of different weights. They first tried a six pound breech loader, 

 aind after firing six rounds they increased the quantity of powder to the 

 service charge, after that they gradually increased the weights of the 

 balls, until they fired one weighing 200 pounds. This ball filled the whole 

 bore of the gun, and projected frouT the muzzle some distance. This would 

 seem to set aside the theory of Mr. Wiard, that the bursting of a gun 

 is occasioned by its thermal condition. Another gun was also tried of 

 larger calibre, from which, by increasing the weights of the ball they 

 eventually fired a steel shot weighing 1,000 pounds, so that it seems there 

 is a gun made to stand the fire of a thousand pound ball. 



City Locomotives or Steam Cars. 



Mr. I. K. Fisher. — I have examined some of the city locomotives or 

 dummj^s, as they are called, used for propelling cars on city railr(>ads, now 

 running from Jersey city to Bergen Point, and about Avhich considerable 

 has been said lately. I did not find anything very new in them to report. 

 They are but littte different from the usual class of dummy engines which 

 were used on the Hudson River Railroad. The cylinders are large, and 

 the steam expanded to low pressure; the chimneys are double, and an inch 

 and a half of sand placed between, which deadens the noise of the exhaust 

 steam. They run about eleven miles per hour, and the jolting at that speed 

 is not much greater than in the ordinary cars drawn by horses. On inquir- 

 ing as to the expense of running these engines, I was informed by the 

 superintendent that they can be run a third cheaper than horses at an ave- 

 rage speed of nine miles an hour. I consider they are superior to horse 

 power, even if they do not have a greater speed than that of horses. I 

 have watched very carefully to see if horses were frightened by them, and 

 I have seen only a few that were so, and I am satisfied that if they were 

 in general use horses would become used to them. I have expressed my 

 opinion against gearing on this class of engines. I see no reason why it 

 should be used particularly on driving wlieols of thirty inches diameter. 

 These engines have gearing, so that the piston makes twy) strokes to one 

 revolution of the driving wheels. I deem it proper to say that in my opin- 

 ion our city rail cars are the worst vehicles we have. The pitching 

 apd jolting in them is often worse than in the stages, far worse than in 

 stages on the Belgian pavement. Improvement is certainly needed in this 

 respect. I consider much of the fault to lie in having loose axles, that is, 

 the play, as it is termed, between the axle,s and the boxes, which in some 

 cases is over a quarter of an inch. Steam cars are, however, superior to 

 horse cars, and more comfortable; and I was surprised to hear from the 

 superintendent the low cost of their running. I have no doubt but tha 



