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Description of a Printing Chronograph. 



ing the hundredths of seconds wheel by an electro- 

 magnet in connection with the standard clock; 3d. 

 The method of printing double or single numbers 

 without stopping the type wheels ; 4th. The method of 

 striking the blow, indirectly using the spring of the ham- 

 mer ; 5th. The method of elevating and locking the ham- 

 mer. The minor details for paying off the paper fillet, 

 inking the type, etc., may be accomplished in various ways. 



The battery power required is about the same as for an 

 ordinary chronograph. Three Grove elements, or six Hill's 

 elements, work the two electro-magnets well. A separate 

 battery of about the same size, is used for the hammer and 

 fillet magnets. 



In point of accuracy, this machine leaves nothing to be 

 desired, and is much beyond what we thought possible. 

 From a vast number of experiments, made by recording 

 automatically the beats of the standard clock, both at the 

 middle and end of the oscillation, the mean error for a 

 single print is found to be about 0.013 sec, equal in this 

 respect to the recording chronograph. The maximum 

 difference in the records of the beats, seldom exceeds 0.03 

 sec, and, we believe, this is as much due to the irregularity 

 in the clock connection as in the running of the machine, 

 since the same thing is found in ordinary chronograph re- 

 cords, where the measures are made from second to second. 



During the building of the machine, which was accom- 

 plished by my assistant, Mr. Foreman, and myself, the 

 past winter, as we could find the time, a great many ex- 

 periments were tried, in the method of regulation, printing, 

 etc. The fast moving train was used to propel the integer 

 seconds, and minute type wheels, dispensing with the aux- 

 iliary movement ; but the disturbance of its motion was 

 considerable, especially at the end of every minute, when 

 it had double duty to perform. "We think, however, by 

 taking the power from the shaft turning once in a minute 



