OF ARTS AND SCIENCES, 225 



added, that Dr. Harris had had few equals, even if the past 

 were inchided in the comparison ; and they were adopted 

 unanimously. 



In accordance with the last resolution. Dr. A. A. Gould 

 was chosen a committee to prepare a Memoir of the Life 

 and Labors of Dr. Harris for publication by the Academy. 



Four Iiundred and tAventy-flftli meeting. 



March 11, 1S56. — Monthly Meeting. 



The President in the chair. 



Professor liOvering exhibited L'' Appai^eil Regulateur de la 

 Luiniere Electrique, as contrived and constructed by M. J. 

 Dnboscq, of Paris, and presented the following translation 

 of his description of the mechanism : — 



" If two metallic wires are attached to the two poles of an ener- 

 getic voltaic battery, and the free ends of these wires terminate in 

 thin rods of compact carbon from gas retorts or of graphite, at the 

 moment when the two carbon rods touch, a vivid spark is seen to play 

 between the nearest points. If the two rods remain in contact, they 

 grow warm gradually up even to a red heat ; next, a part of the 

 carbon is inflamed, burns, and disappears ; another portion seems to 

 be volatilized, and litde by little the two extremities of the carbon 

 rods, which touched one another, separate more and more, from waste 

 of material, without on this account any cessation of the current cir- 

 culating in the pile, the wires, and the carbon rods. The part of the 

 rods which has disappeared is found to be replaced by a luminous 

 purple jet, in which incessantly whirls an incandescent vapor of 

 carbonized particles, which the negative pole seems to abstract from 

 the positive pole, or which the latter projects towards the former. The 

 distance between the carbon points has a limit, depending on the in- 

 tensity of the current, beyond which the purple light is extinguished, 

 the incandescent jet ceases, and the current is interrupted. In a 

 vacuum this distance is much greater than in air, since the elec- 

 tricity, not having the atmospheric pressure to overcome, darts from 

 the carbon even before the points have arrived at contact. But the 

 carbon, which is volatilized and condensed upon the sides of the re- 



voL. HI. 29 



