618 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



neering difficulties in the way. There has always been a hankering after 

 something very difficult in order to engage popular attention. AVithin five 

 years we shall have a railroad in Broadway, and we will then look upon it, 

 as we have at the steam fire engine, and wonder why it had not been in- 

 troduced before. The greatest objection to street railways is the liigh fare. 

 A passenger can be carried for three cents and the companies would pay a 

 fair dividend. 



The Chairman enquired whether any gentleman present had been in tke 

 London railway tunnel ? 



Prof. Joy, of Columbia college, stated that he had made a passage 

 through a portion of the railway tunnel alluded to. It was very comforta- 

 ble and pleasant. The tunnel appeared to be amply ventilated and lighted. 

 At every fifth or sixth block there were openings for the ingress and egress 

 of passengers. 



Dr. Parmelee said the great point to be gained was expedition. People 

 could not be carried fast enough. 



Mr. Bartlett suggested that this point might be attained by the use of 

 the pneumatic tube. 



This plan had been discussed at a previous meeting. After some further 

 observations from Mr. Adriance and others, it was decided to take up the 

 question again. 



Geological. 



Dr. Stevens illustrated, with the aid of diagrams, the peculiar move- 

 ments which have taken place in the great upheaval, producing the moun- 

 tain system, from the Atlantic coast to McKeon county, Penn. The range 

 through which the Potomac river passes was particularly noticed. The coal for- 

 mation, the Devonian and the Upper and Lower Silurian systems, were 

 pointed out. The same strata of coal in the valleys were found on the tops 

 of the mountains. Faults occurring at various points through which the 

 river passed were shown; these cannot be explained without diagrams. 

 The speaker was listened to with evident satisfaction. 



Iron and its Application to War Vessels. 



The Chairman, in announcing the selected subject for discussion, stated 

 that Mr. Charles W. S. Heaton had been invited to address thorn, and he 

 would probably devote part of his remarks to the proper use of iron in 

 building ships of war. 



Mr. Heaton, after some preliminary remarks, directed attention to the 

 nature and peculiarities of iron. The three most important varieties are 

 cast iron, hammered iron and rolled or bar iron. 



Cast iron is a crystalline metal, having comparatively little tensile 

 strength, but presenting great resistance to compression. It is made 

 malleable in small castings by being subjected to long continuous Jieat, 

 "which blends together its crystals, thus rendering it tougher and less brit- 

 tle. The surface of cast iron is made more hard but brittle if it is poured, 

 when melted, into damp molds, producing what is called chilled cast iron. 



In hammered and rolled iron the crystalline arrangement is entirely de- 



