484 Prof. B. Silliman on a Granular Alhite 



Experiments of September 29. 



(A Bunsen's battery of 30 elements, well-cleaned and amal- 

 gamated, was employed.) 



First Series. 



Without current 

 Current A . . 

 Current B . . 



Without current 

 Current B . . 

 Without current 



Deviations. 



12-0 



14-9 



8-6 



11-7 



8-8 



11-8 



Second Series. 



Without current . . . 18*4 



Current B 14-9 



Current A 21-7 



It is to be remarked, that here, if the principal sections of the 

 prisms were perpendicular, the deviation, at first null, would 

 scarcely attain one semi-division when one of the currents was 

 made to act. 



Lastly, to obviate every objection, a third series of experi- 

 ments was made by taking away the prism of flint-glass, and 

 observing the deviations produced by the solar ray, when, as 

 before, the electric current was made to pass in the wires of 

 the electro-magnet, now in one direction, now in another. 



Devia-^ As should be the case, the deviations are 

 tions. I equal, which proves that the electric cur- 

 Current A ... 16*5 Vrent and the magnet change the devia- 

 Current B ... 16*8 tions in acting on the flint-glass and not in 

 Current A ... 16"8 J acting on the needle of the galvanometer. 



The above experiments establish, we believe, in an irre- 

 fragable manner, the rotation of the plane of polarization of 

 heat under the influence of magnetism. 



LIX. On a Granular Albite associated xvith Corundum, and 

 on the Indianife ofBournon. By B, Silliman, Jun., M.D., 

 Professor of Chemistry applied to the ^rts in Yale College, 

 and of Medical Chemistry and Toxicology in Louisville Uni- 

 versity, Kentucky^. 



A SPECIMEN of a granular mineral was sent me by 

 Mr. Gibbs of Andover, last year, with the remark that it 

 was found in beds in Lancaster County, Pennsylvania, and 



• From Silliman's Journal for November 1849. 



