706 Transactions of the American Institute. 



the end of the trunk opposite to the crank-shaft, thus nearly doub- 

 Hng its length, and greatly reducing the angle at which it works. 

 By this arrangement all side strain or wear is removed, and the point 

 of connection is easily accessible. Mr. Root also explained that 

 the compactness of the engine was one of its claims of merit, and 

 showed the advantages of a quick-running engine over that of a 

 slow one. 



The usual hour of adjournment having then arrived, no other 

 engines were explained; and the meeting was declared adjourned 

 ■for one week. 



October 17, 1867. 

 Prof. S. D. Tillman in the chair; J. Wtatt Rkio, Esq., Secretary. 



The Chairman opened the proceedings by reading the following 

 summary of scientitic news: 



raU'ROVED SWmG-SPAN. 



The great swing-span in the new iron bridge across the Harlem 

 river, connecting the city of New York with Westcsester county, 

 is moved over half a circle, having a circumference of five hundred 

 and sixty-five feet, by means of water power supplied by the Croton 

 aqueduct. The engine is so arranged that either water or steam 

 may be used as the motor. 



GREAT RAILROAD BRIDGE. 



The bridge now building across the Mississippi, at Quincy, will 

 be completed in September, 1868. It will be the longest bridge 

 on piers in the United States, and will mejisure one mile and four 

 rods. Its main draw is three hundred and sixty feet in length; it 

 has a smaller draw eighty feet long; both are worked by steam. 

 The estimated cost of the bridge is $1,250,000. 



THE ANEROID BAROMETER. 



Dr. Stewart, of the Kew Observatory, has made a series of 

 experiments with this barometer, under different pressures, and 

 concludes that on taking this barometer up a mountain twelve 

 thousand feet high, it would indicate the true height within three 

 hundred feet. There are, however, serious objections to the 

 metallic barometer, not fully set forth by Mr. Stewart, which should 

 prevent its use for strictly scientific purposes. 



