162 Scientific Intelligence. 
of their lamp narrow at the top, and thus increasing the capillary ac- 
tion of the wick, obtained a light which might be compared to that of 
lamps of a constant level. Masson-Moinat, Milan and Osmond, in- 
dependently of the use of capillary tubes, have modified their lamps 
80 as to keep them at a constant level, a condition essential to a lamp 
with a double air current. The disposition of their lengthened re- 
servoir renders the use of this apparatus easy, without loss of oil, 
which is not unimportant to those who use them. Experience has 
proved that in both of these lamps, the wick, though raised seven 
millimetres, (one fourth of an inch,) above the beak, is carbonized 
only two millimetres during the combustion of the oil. This eleva- 
tion of the wick above the beak, has the further advantage’of not be- 
ing deteriorated, nor even blackened, whence it results that these 
lamps have rarely any need of being cleaned. We propose to the 
Academy, that it approve this apparatus, and testify to the inventors, 
the interest which it takes in the perfection of these hydrostatic lamps 
with a double current.”—(Adopted.)—Idem. 
3. Watkins’ dry Galvanic battery.—Prof. De Rive, in his 2e- 
count of this pile, (noticed in a former number,) states that the plates 
must be at a very small distance from each other, (<5 or 435 inch,) 
so as to be separated by a very thin stratum of air. Humidity favors 
the action of the instrument, the results of which tend to confirm the 
purely chemical theory of Voltaic electricity, for there is here no 
point of contact of heterogeneous metals, and the developement of 
electricity appears to be due uniformly to the oxidating action of the 
air. ‘The trough itself must serve as a conductor, for he has ascer- 
tained that with a very dry wooden trough, the effect is much less, 
and that when the plates are connected simply by glass rods with @ 
little cement, the effect ceases. Hence, in common Voltaic batte- 
ries, the liquid acts two distinct parts, viz. as an exciter, and as @ 
conductor. In this dry battery, the air is the exciter, and the trough 
itself the conductor ; and the example proves that if the chemical 
action be not equally intense upon the two surfaces of the metal, 
there is no absolute necessity of contact between two heterogeneous 
surfaces for the developement of electricity. —Jdem. 
_ 4. Eccentricity of Saturn’s Ring. —Extract of a letter from 
ponent to Prof. G. Maurice, one of the Editors of the 
