Description of a Printing Chronograph, 69 



sumed for this operation is about three-tenths of a second, 

 allowing, therefore, observations to follow each other at a 

 minimum interval of one-half secoud. "When the hammer 

 is elevated it is locked, by an electro-magnet, the operating 

 of this magnet allowing it to fall and print. The armature 

 time of the hammer is about 0.07 sec. ; being but little in 

 excess of our ordinary chronographic recording pen. 



The types are inked by means of small rollers, covered 

 with cloth, resting against their rim, and revolving with 

 the wheel by friction. These rollers require inking every 

 two or three days. If desirable, the inking rollers may be 

 dispensed with, and impression paper used instead. After 

 numerous experiments made with both methods, we have 

 preferred the ink. 



The paper fillet two inches in width, is wound on a small 

 spool, holding about 40 feet, and drawn between two rollers, 

 the same' as a Morse Kegister. Every time the hammer 

 falls, the fillet is advanced about one-quarter of an inch, by 

 the action of an escapement driven by a weight. One 

 spool of paper will hold about 1,200 observations, includ- 

 ing the spacing for different objects. This same escape- 

 ment is also operated by an electro-magnet, under the con- 

 trol of the observer ; who by pressing a key is able to make 

 spaces of any width between the prints. 



The train carrying the minutes and integer seconds, will 

 run eight hours ; the gear for elevating the hammer will 

 deliver 2,000 blows ; and the train for moving the paper 

 fillet will go 1,200 times without winding. The fast mov- 

 ing train runs one hour and thirty-six minutes ; but since 

 this train can be stopped at pleasure without changing the 

 zero of the type, its comparatively brief running is not a 

 serious inconvenience. 



To recapitulate, we claim the following principal points : 

 1st. Separate movements for the integer seconds, and 

 the hundredths of seconds ; 2d. The method of regulat- 



