Description of a Printing Chronograph. 



71 



and giving uniform motion to the type, it might be suc- 

 cessful ; but nothing would be saved in the amount of ma- 

 chinery and the liability of losing integer seconds from 

 accidental disturbance, would be a serious imperfection in 

 the method. As now constructed, there is hardly a possi- 

 bility of error in the integer seconds, without a serious 

 disarrangement of the mechanism. If the fast running 

 train is stopped entirely, it only requires about six seconds, 

 to bring it again in coincidence with the clock pendulum. 



The saving of time and labor by the use of a printing 

 chronograph is very considerable. At the lowest estimate, 

 it does work equivalent to the labor of one person where 

 three are employed at the same time. In our zone work 

 in former years, when the zone extended two hours in 

 right ascension, it usually required the labor of two per- 

 sons a whole day to convert the chronographic records into 

 numbers and copy them on the blank forms. With the 

 observations printed, this labor is wholly dispensed with ; 

 since the " mean"' is at once deduced from the printed 

 record. 



The machine is readily adjusted to indicate the same 

 numbers as the clock's face, the type being so set as 

 to print zero-hundredths when the pendulum is at its 

 lowest point, where the magnetic circuit is completed. In 

 the construction of the apparatus, provision was made for 

 attaching engraved rings to the type-wheel shaft, showing 

 at a glance the time. But these are found not essential, 

 as they would but little facilitate the setting of the type, 

 which is accomplished as follows : The minute type-wheel 

 which is free to move in either direction, is revolved to 

 correspond to the correct minute, an impression may then 

 be taken, and the machine started when the clock indi- 

 cates the same ; the seconds being readily counted from the 

 beats of the magnet regulating the fast moving train. The 



