Description of a Printing Chronograph. 67 



any other proposed, is based on the principle of using 

 separate systems of mechanism for the fast-moving type 

 wheel, and those recording the integer minutes and seconds, 

 regulating each with electro-magnets controlled by the 

 standard clock. 



For a clear understanding of the mechanism, elaborate 

 drawings would be necessary. We shall, therefore, merely 

 give a general account of its construction and peculiarities : 



1st. A system of clock-work carrying a type-wheel with 

 fifty numbers on its rim, revolving once every second ; one, 

 two, or parts of two numbers being always printed, so that 

 hundredths of seconds may be indicated. This train is 

 primarily regulated to move uniformly by the Frauenhaufer 

 friction balls, and secondarily by an electro-magnet acting 

 on the fast-moving type-wheel, controlled by the stand- 

 ard clock. This train i3 entirely independent, and can 

 be stopped at pleasure, without interfering with the other 

 type wheels. 



2d. A system of clock-work, consisting of two or more 

 shafts, carrying the type-wheels indicating the minutes and 

 seconds. The motion of this train is also governed by an 

 electro-magnet, controlled by the standard clock, operat- 

 ing an escapement, in a manner analogous to the action 

 of an ordinary clock; every motion of the escapement 

 advancing the type one number. 



There are three type-wheels, indicating minutes, seconds 

 and hundredths of seconds. The integer seconds are ad- 

 vanced at every oscillation of the standard pendulum ; and 

 the minute, at the end of each complete revolution of the 

 seconds wheel. 



The type wheels are constructed of brass disks, around 

 the circumference of which is soldered a strip of electrotype 

 copper holding sixty numbers. 



Presuming now we have this system of type-wheels in 

 operation, it is necessary to print without disturbing their 



