244 /. Locke on the Electro-Chronograph. 



netism, instead of by weights, has been invented in England. 

 This is truly a magnetic clock, and Dr. Locke's attachment or 

 contrivance for subdividing seconds may be connected with the 

 magnetic clock as readily as with any other. At any rate, with- 

 out going into the fitness of terms, the expression " Magnetic 

 Clock," is not descriptive of Dr. Locke's invention * But as a 

 practical illustration of the value of Dr. Locke's invention, I may 

 mention the fact, that we have for four years been making ob- 

 servations here continually for the purpose of determining the 

 longitude of this place. After we shall have been at work for 

 twice that time — I might say for a life-time — if we succeed in 

 determining the longitude of the Observatory within the limits of 

 the lot in which the building stands, seventeen acres, we should 

 consider ourselves as well repaid for the labor and time employed. 



Now with Dr. Locke's invention, the difference of longitude 

 between this Observatory and any other point, reached by mag- 

 netic telegraph, may be determined in one night so closely as to 

 show in what part of the building the observations were made. 



And thus, by having one of Dr. Locke's clocks here, this Ob- 

 servatory may be connected with every other observatory in the 

 country in such a manner as to make all their observations for 

 their longitude from Greenwich to other European observatories, 

 available for determining our longitude also from the same places. 



It will enable the Observatory in a single night to determine 

 the difference of longitude between the capitol to any other place, 

 reached by magnetic telegraph, with far more accuracy than it 

 can be done without it, and thus enable this Observatory to fulfill, 

 in the most satisfactory manner, one of the most important ob- 

 jects of a National Observatory, viz : that of perfecting the geog- 

 raphy of the country and of affording in different parts of it well 

 and accurately determined points of departure for the traveller, 

 the surveyor and the navigator. 



It will enable the observers now employed here to do double, 

 perhaps treble, the quantity of work that they now do, and to do 

 it better. 



The instruments require five clocks ; — with Dr. Locke's im- 

 provement applied to one of them, all the others may be dispens- 

 ed with. 



I might go on in the enumeration of the advantages to the 

 public service, the facilities and the powers which this invention 

 give the astronomer, were I at liberty to explain the principles 

 and give descriptions of the invention in its present state ; suffice 

 it to say, that ingenuity has been successfully exercised to such 

 an extent in the matter, that, though there be six astronomical 

 instruments here, one of these clocks will record the observations 



Dr. Locke's invention is now called the " Electro-Chronograph. 



