90 Dr J. B. Pearson, On Sympathetic Needles. [May 9> 



(2) On Sympathetic Needles. By J. B. Pearson, D.D. 



I propose in this paper to give a historical sketch, as well as I 

 can trace it out, of the notion prevailing some hundred years ago, 

 as to the possibility of magnetic signalling between places at some 

 distance from one another. After a description of the idea itself, 

 I will state how and when it seems to have arisen — and passed 

 into obscurity. 



The notion itself is perhaps most neatly explained by Addison, 

 in the Spectator, No. 241 (Dec. 6, 1711). 



"Strada, in one of his Prolusions, gives an account of a chi- 

 merical correspondence between two friends by the help of a 

 certain Loadstone, which had such virtue in it, that if it touched 

 two several needles, when one of the needles so touched began to 

 move, the other, though at never so great a distance, moved at the 

 same time and in the same manner. He tells ns that the two 

 friends, being each of them possessed of one of these needles, made 

 a kind of dial-plate, inscribing it with the four and twenty letters, 

 in the same manner as the hours of the day are marked upon the 

 ordinary dial-plate. They then fixed one of the needles on each 

 of these plates in such a manner, that it could move round without 

 impediment, so as to touch any of the four and twenty letters. 

 Upon their separating from one another into distant countries, 

 they agreed to withdraw punctually into their closets at a certain 

 hour of the day, and to converse with one another by means of 

 this their invention. Accordingly when they were some hundred 

 miles asunder, each of them shut himself up in his closet at the 

 time appointed, and immediately cast his eye upon his dial-plate. 

 If he had a mind to write anything to his friend, he directed his 

 needle to every letter that formed the words that he had occasion 

 for, making a little pause at the end of every word or sentence, to 

 avoid confusion. The friend in the meanwhile saw his own sym- 

 pathetic needle moving of itself to every letter which that of his 

 correspondent pointed at. By this means they talked together 

 across a whole continent, and conveyed their thoughts to one 

 another in an instant over cities or mountains, seas or deserts. 



" If Mons. Scudery or any other writer of romance had intro- 

 duced a necromancer, who is generally in the train of a knight 

 errant, making a present to two lovers of a couple of these above 

 mentioned needles, the reader would not have been a little pleased 

 to have seen them corresponding with one another, when they 

 were guarded by spies and watches, or separated by castles and 

 adventures. In the meantime, if ever this invention should be 

 revived or put in practice, I would propose that on the lover's 

 dial-plate there should be written, not only the four and twenty 

 letters, but several entire words which have always a place in 



