PHILOSOPHICAL SOCIETY OF WASHINGTON. 29 



Mr. S. F. Baird made a comraunication on 



THE ARTIFICIAL PROPAGATION OF THE COD, 



describing the measures and process adopted at Gloucester, Mass., 

 and the success thus far obtained. A vessel is to be specially 

 constructed for the Fish Commission, to be used for this purpose. 



Mr. Elliott made some remarks and inquiries respecting the 

 extent of the cod fisheries. 



Mr. P. H. Dudley, C. E., made a communication, illustrated 

 by drawings, on 



THE USES OF HIS DYNAGRAPH, AND THE WORK PERFORMED IN 

 DETERMINING THE RESISTANCE OF RAILWAY TRAINS, ETC. 



(abstract.) 



It is an instrument designed for the purpose of determining, 

 and graphically recording on a continuous sheet of paper, the 

 resistance to traction of railway rolling stock of all kinds, either 

 as single cai's or in trains; also, testing the resistance to traction 

 of locomotives of various kinds of wheel base, and also their 

 capacity; the object being to obtain data from a knowledge of 

 which the cost of transportation may be reduced, by substituting 

 facts for mere opinion. 



It has several attachments, so that data can be obtained to 

 solve most of the problems connected with the movement of trains. 

 The low joints in the rails are also shown at the same time. 



The wearing effect on the rails and tires of various kinds of 

 wheel base of locomotives can also be shown by special experi- 

 ments. A car is specially constructed for its use ; the present 

 one is 50 feet long by 9 feet 6 inches wide, and has five apart- 

 ments, viz.: 1st. Dynagraph room with bookcase: 2d. Sleeping 

 room: 3d. Laboratory: 4th. Sitting room; one double overhead 

 berth, piano, wardrobe, and washstand : 5th. Dining room, con- 

 taining range, ice box, provision drawers, china cupboard, and 

 portable table. An aisle on one side of the car permits access 

 to any apartment. The instrument is placed near the end of the 

 car in the Dynagraph room. 



The car has two 4-wheeled trucks, each with 7 feet wheel base, 

 all the wheels being turned truly cylindrical. The elliptical 

 springs in the trucks are quadruplets, so that the car rides very 

 steadily on most roads. The draw-bar is enlarged, and a steel 

 cylinder 6 inches long and 4 inches internal diameter inserted 

 instead of the usual fastening. In each end of the cylinder pis- 

 tons with cup-leather packing are inserted and by means of an- 

 nular rings both are free to move in, but prevented from moving 



