312 



representing the changes of magnetic declination, as recorded 

 at the Magnetic Observatory of Mr. Bond, at Cambridge, and 

 at the Girard College, on the magnetic term day of May, 1840, 

 and showing that the changes attending the aurora are not pe- 

 culiar to one locality, but that, as observed at different places, 

 they are parts of a great magnetic disturbance. 



The two curves thus presented agreed remarkably in all their ge- 

 neral features, showing, as a general result, similar motions of the 

 needle at the two places in direction, though not always proportional 

 in amount. They presented remarkable differences in the absolute 

 times at which these movements had taken place at the two sta- 

 tions, the similar movements differing frequently five minutes (with 

 opposite signs), and in a few cases as much as ten minutes in time; 

 in other cases being simultaneous. The period at which the needle 

 had attained, suddenly, its greatest deviation from the true meridian, 

 was ten minutes earlier in absolute time at Cambridge, than at Phi- 

 ladelphia. 



Mr. Justice reported, that during the last four or five even- 

 ings, he had tested the value of the telescope referred to at a 

 former meeting of the Society (Proceedings, No. 13, p. 276), 

 by observations on the Moon, and stated his opinion of its ex- 

 cellence, as deduced from those observations. Mr. Justice de- 

 tailed the appearances presented by the Moon's surface through 

 this instrument. 



. Dr. Demme referred to the contents of a circular letter from 

 Germany, in which it was stated, that a number of gentlemen 

 of Stuttgart had united, under the name "Societas Bibliophilo- 

 rum Stuttgartiae," to publish historical and antiquarian works, 

 which are either out of print, or have never been printed. 



The Society at Stuttgart will begin to publish as soon as they have 

 procured five hundred subscribers. The subscription is one pound 

 sterling for which the subscriber will receive one copy : and no more 

 copies will be printed than are subscribed for. The letter to Dr. 

 Demme, which accompanied it, requested the honour of enrolling the 

 American Philosophical Society amongst the subscribers. 



On motion, the Society resolved to subscribe to the under- 

 taking. 



