THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



MAY 1850. 



XLI. Observations on a remarkable Exudation of Ice from 

 the Steins of Vegetables, and on a singular Protrusion of Icy 

 Columns from certain kinds of Earth during frosty weather. 

 By John LeConte, M.D., Professor of Natural Philosophy 

 arid Chemistry in the University of Georgia*. 



IT is certainly a remarkable circumstance, that phaenomena 

 so striking as those forming the subject of this paper have 

 received so little attention from philosophers ; and it is per- 

 haps still more singular, that hitherto no attempts have been 

 made at their explanation. Stephen Elliott, in his Sketch of 

 the Botany of South Carolina and Georgia, published in 1824, 

 notices a remarkable protrusion of crystalline fibres of ice from 

 the stems of the Conyza bifrons (vol. ii. p. 322). Sir John F. 

 W. Herschel published a short notice of a similar exudation 

 of icy fringes occurring around thistle-stalks and stumps of 

 heliotropes, in the London and Edinburgh Philosophical 

 Magazine for February 1833, p. 1 10 (3rd series, vol. ii. p. 1 10)t. 

 Professor S. P. Rigaud of Oxford notices the occurrence of 

 an analogous phaenomenon on a recently built stone wall, in 

 the succeeding Number of the same Journal (3rd series, vol. ii. 

 p. 190. 1833). As far as my researches extend, the above- 

 mentioned notices — all of them very brief and imperfect — 

 embrace all the observations hitherto made on these remarkable 

 phaenomena. Even the natural speculative tendency has been 



* Communicated by the Author, having been read before the American 

 Association for the Advancement of Science, at their extra meeting at 

 Charleston, South Carolina, March 12, 1850. 



t James D. Dana appears to have noticed the same phaenomenon. He 

 says, " On the cool mornings of spring or autumn in this climate, twigs of 

 plants are occasionally found encircled by fibrous icy curls, which are at- 

 tached vertically to the stem.' (Vide Manual of Mineralogy, 2nd Ed. 

 p. 46. New Haven and Philadelphia, 1849.) 



Phil. Mag. S. 3. Vol. 36. No. 24-4. May 1850. Z 



