Miscellanies. 399 



Warmest day 23d; coldest 15th. 



Highest degree S8 ; lowest 23, range 65. 



7th. Primrose in blossom. 8th. Dandelion and plumtree in 



blossom. 9th. Cherry and shadbush in blossom. 12th. Snow 



squalls; 13th. and 14th ground covered with snow most of the time, 



•at times more than one inch in depth. — Surface of the earth much 

 frozen. 



20th. Apples in blossom. 



23d. Violent wind with thunder and lightning at 5 o'clock in the 



P.M. 



20. Influence of Electricity on Capillary Attraction. 



Extract of a letter from Jno. W. Draper to the editor, dated Christiansville, Meck- 

 lenburg, Va., May 31st, 1832. 



To Prof. Silliman. — Sir — Without a personal acquaintance, 



I write to inform you of some scientific points of interest which have 



recently been made known in England, but which from the lateness 



of the discovery have not I believe been published in this coun- 

 try. 



You will remember, that Laplace in his Theorie de Taction ca- 

 pillaire in the supplement to the tenth book of the Mecanique Celeste 

 (after shewing how the + or — action of the bounding meniscus of 

 a liquid in a capillary tube determines its position therein) leaves the 

 nature of the force of capillary attraction entirely out of the question; 

 the adhesion of plates of glass to the surface of liquids he allows to 

 depend on the same cause. It was in investigating the latter phe- 

 nomenon that the mystery of all these singular appearances was dis- 

 covered. I will indicate, as succinctly as I can, the chain of rea- 

 soning. 



If you place a disc of glass upon the surface of mercury and at- 

 tempt to lift it, you will immediately be sensible of a strong attraction 

 between them ; the value of that attraction is measurable by the bal- 

 ance. Whilst the glass is reposing on the mercury, if the latter is 

 connected with a sensible gold leaf electrometer you will not find the 

 smallest indication of developed electricity. But on separating them 

 by means of a fibre of gum lac fastened to the back of the glass, the 

 gold leaves, in a moment, diverge, and the glass disc is found to be 

 electrified, oppositely, to an equal amount— place them in contact and 

 all electrical signs vanish. 



