193 



Arsberattelse om Framstegen i Fysik och Komi afgifvcn don 31 

 Mars, 1839; afJac. Berzelius. 8vo. Stockholm, 1840. — From 

 the Royal Swedish Academy. 



Kongl. Vetenskaps-Academiens Ilundlingar. For ar 1839. 8vo. 

 Stockholm, 1841. — From the same. 



Arsberattelse om Technologiens Framsteg. Till Kongl. Vetenskaps- 

 Academien afgifven den 31 Mars, 1839; af G. E. Pasch. 8vo. 

 Stockholm, 1840.— From the same. 



Tal af Academiens Presses, Grefve M. Rosenblad. 8vo. Stockholm, 

 1840. — From the same. 



Journal of the Franklin Institute. Third Series. No. 6. For June. 

 Philadelphia, 1842. — From Dr. Patterson. 



Proceedings of an Indian Council, held at the Buffalo Creek Reserva- 

 tion, State of New York. Fourth Month, 1842. 8vo. Balti- 

 more, 1842. — From Mr. G. M. Justice. 



Professor Henry, of Princeton, presented the record of a se- 

 ries of experiments on induction from ordinary electricity, as 

 the fifth number of his Contributions to Electricity and Mag- 

 netism, which was referred to a Committee. Of these experi- 

 ments he gave a verbal account, of which the following is the 

 substance. 



In the third number of his Contributions he had shown on this sub- 

 ject: 1. That the discharge of a Ley den battery through a conductor 

 developed, in an adjoining parallel conductor, an induced current, 

 analogous to that which, under similar circumstances, is produced by 

 a galvanic current. 2. That the direction of the induced current, as 

 indicated by the polarity given to a steel needle, changes its sign with 

 a change of distance of the two conductors, and also with a change 

 in the quantity of the discharge of electricity. 3. That, when the in- 

 duced current is made to act on a third conductor, a second induced 

 current is developed, which can again develope another, and so on 

 through a series of successive inductions. 4. That, when a plate of 

 metal is interposed between any two of the consecutive conductors, 

 the induced current is neutralized by the adverse action of a current 

 in the plate. 



The direction of the induced currents in all the author's experi- 

 ments was indicated by the direction of the polarity given to steel 

 needles inclosed in a spiral, the wire of which formed a part of the 

 circuit. But some doubts were reasonably entertained of the true in- 

 dications of the direction of a current by this means; since M. Savary 



