/. Locke on the Electro- Chronograph. 237 



minutes and seconds, made by the clock itself acting as an au- 

 tomaton operator. Second, the record of any event made by the 

 hand of the observer, in the midst of the seconds, in such a man- 

 ner as to indicate the precise fraction of a second at which it 

 occurred. 



First, then, the Automatic record of time. — By the Automatic 

 Clock, the fillet will be marked to indicate seconds of time, thus : 



In this specimen, lines and breaks are represented instead of 

 dots and lines as described in my last. The beginning of a 

 minute will be indicated by the omission of a break and the run- 

 ning together of two lines, thus: 



The middle of this long line is then the beginning of a minute. 

 The beginning of ten minutes will be shown by the omission of 

 two breaks, and the beginning of every hour by the omission of 

 three breaks when four lines will run together. 



Second, of the Manual record of any special event. — The com- 

 mencement of an eclipse, the noon-point of the sun, or of a star, 

 or any other event desirable to be marked precisely, is registered 

 by the observer by breaking the circuit at any point by hand : 

 this will appear in the fillet thus: 



In this example the event is recorded at four seconds and four- 

 teen-hundredths of a second, the point [indicating the event] 

 being the commencement of the break. 



The apparent obliteration of the breaks, indicating seconds, by 

 omitting two or three [as in indicating the commencement of 

 every ten minutes and every hour J or a blank for a second or two, 

 creates no difficulty, for they can obviously be restored by a pair 

 of dividers. The complete circuit [for this operation] will then 

 include a battery, register* and keys as usual (keys for breaking 

 the circuit), and besides these, the Automatic clock. The ob- 

 server and key must be at the place of [observing] the ' ; event, 5 ' 

 say at St. Louis, while the other parts may be ever so remote, 



Wash 



>/ 



of Dr. Locke's " Chronograph," from the pen 



P 



The following account of this late invention, from an article 

 furnished by Coast Survey Assistant, Sears C. Walker, to the 

 United States Gazette, is a" perfectly graphic and true picture of 



i 



* See Note, page '235. 



