I 



J. Locke on the Electro-Chronograph. 233 



mencement happens in the letter break, the ending will be in the 

 midst of a proper line. 



7. That this point of the necessity of a circuit nearly contin- 

 uously closed, is rather a blind one, is evident from several facts. 



a. I did not perceive it clearly myself without some study. 

 b. In my correspondence with Dr. Bache, he suggested that" I 

 should improve my invention by marking seconds by dots and 

 blanks, when I explained to him the impossibility of doing so 

 under the conditions assumed, unless by a reverse arrangement, 

 generating blanks while the circuit is closed, a thing possible with 

 Morse's registering instrument, when still the circuit would be as 

 before, mostly closed, c. Prof. Mitchel, of Cincinnati, in an 

 attempt to anticipate me in the result of my researches, used an 

 mterruptor invented by me three years previous, though I pre- 

 sume unknown to Prof. M., and succeeded in marking dots on a 

 Morse fillet. The interrupter was the pendulum rod swinging, at 

 its lower end, through a globule of mercury, the pendulum and 

 the mercury being connected with the battery poles. When 

 Prof. M. informed me of what he had been doing, for I knew 

 nothing of it until I had finished my invention, I asked him if 

 he had imprinted observations upon this dotted fillet. He an- 

 swered that he had not, but he thought he could do it. I asked 

 him how. He replied that he would break the circuit. I remind- 

 ed him that breaking his circuit would merely obliterate his dots, 

 and asked him how he would mark an event which should occur 

 fractionally between the dots. He admitted the impossibility. 

 d. \arious individuals of good attainments have expressed them- 

 selves unable to perceive the peculiarities which I have just de- 

 scribed, e. One individual expressed his intention of making a 

 clock perform chronographically by means of a dotting register, 

 but in the execution he found the necessity of changing his plan. 



When the clock is near the operator so that he can have an 

 extra circuit to it, or when he is at the registering instrument so 

 that he can strike in his observation-marks positively by hand, or 

 by an extra circuit, then a dotting registration can evidently be 

 adopted. 



8. By way of further defining the electro-chronograph, per- 

 mit me to introduce a brief history of the invention from a work 

 which you perceive is printed but not yet published. 



My attention was first drawn practically to the subject of the 

 combination of clocks and electrical machinery for producing 

 useful results, in 1844 and '45. I was delivering a course of pop- 

 ular lectures at Cincinnati on Electrology. My object was not 

 ■? much to reduce any thing to a complete system in actual prac- 

 tice, as to show the essential elements of what was actually prac- 

 ticable. Having commenced and continued my studies of elec- 



Seconp Series, Vol. VIII, No. 23.— Sept, 1849. 30 



