PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 359 



Mr. Dibben. — It has been extensively experimented on, and found to be 

 many times more expensive than steam. 



Mr. Fisher pro'posed tlie " Making- of Common Roads," as the subject 

 for discussion at the next meeting, which was adopted. 



Adjourned. Enos Stevkns, Secretary pro tern. 



American Institute Polytechnic Association, ) 

 September \l, 1862. ) 



Dr. R. P. Stevens in the chair. 



Mr. J. K. Fisher read a paper as to steering vessels by means of a rudder 

 placed in the bow. The principal advantage claimed is that it would be 

 out of the way of the screw, and the main difficulty is to keep it firm 

 against violent waves, and to bring it from one side to the other in changing 

 course. He proposes to hold and to move the rudder by means of a 

 hydraulic press. 



Mr. Babcock objected that a bow rudder would foul badly by drifts 

 between the ship and rudder. 



]\lr. Dibben objected that it would be extremely difficult to handle a bow 

 rudder with sufficient power and speed. 



Mr. E exhibited a bolt made of wire rope, so as to be elastic, and 



especially not to break off while holding armor plates when hit, nor while 

 fastening standing rigging. 



Mr. Dibben thought tliat it would rust much faster than if all in one bar. 



The price of such bolts is 616 [)er 100 pounds. 



Adjourned. Enos Stevens, Secretary pro tern. 



American Institute Polytechnic Association 

 September 18, 1862. 



'} 



Mr. John P. Veeder in the chair. 



Mr. Fisher asked what was the speed of war steamers. 



Mr. Dibben. — Probably ten knots when in fighting trim; and yet some- 

 times, in ballast, may attain thirteen or fourteen; and commercial steamera, 

 with strong and favorable wind, sometimes about sixteen knots. , 



Prof. Seely explained the aspirator, an instrument through which water 

 and air flow, adapted to aerate water, to produce cheaply a strong and 

 steady current of air for the blowpipe, and to ventilate rooms, where a 

 current of water is available to propel the air. A small stream of water 

 enters the side of a larger perpendicular open tube, and, by its gravity, 

 carries down the air in the larger tube continually, propelling out the air 

 with great force from the bottom of the large perpendicular tube, and 

 taking in more air all the time at its open top. 



Mr. Bartlett explained the electro-ballistic machine, for testing the 

 Telocity of missiles from guns, etc. The principle of this machine is that 



