TRANSACTIONS OF THK 



[NOV. 3, 



Fig. II. 



In Fig. II., on either side, may be seen the paper drums, one 

 of which is filled with paper before starting out on a trip ; 

 abont 1350 feet in length of 60 pound paper can be put on one 

 drum, sufficient for a trip of 150 miles, when inspecting track. 

 As the car moves, the paper is drawn through the instrument, 

 under the various pens, by the opposite pair of feed rolls, and 

 wound upon the other drum or run on to a table for counting 

 and tabulating the data as the trip is made. The paper is fed 

 through the feed rolls, in exact proportion to the distance run — 

 the paper drums being simply receptacles for the paper, and 

 only affect the proper tension as it is being paid off or re-rolled. 



By change gears, the feed rolls will pass either one inch of 

 paper for each 50 feet, 100 feet, or 200 feet of track, as may be 

 desired, using respectively 8.8 feet, 4.4 feet, 2.2 feet of paper 

 per mile. The first mentioned scale is alw^ays used when in- 

 specting the track. The shaft which drives the entire machinery 

 from its connection with the axle of the car is seen near the left 

 corner of the figure, while many of the other shafts, which 

 opei'ate special indicators, are also seen. 



In Fig. II. are seen the pens, each of whicli gives special in- 

 dications. On the uppei" side, the pen which gives the dyna- 

 mometrical curve ; in the centre, the different electi'ic recording 



