i 
414 Scientific Intelligence: 
views, and calls attention moreover to the fact that the greatest 
outbursts of i igneous rock in the various formations appear to be - 
in all cases connected with rapid accumulation over limited areas, 
causing perhaps disruptions of the crust, through which the semi- 
fluid stratum may have risen to the surface. He cites in this 
connection the traps with the palseozoic sandstones of Lake Su- 
peri ior, and with the mesozoic sandstones of Nova Scotia and the 
Connecticut and Hudson valleys. 
It may ee happen that the displaced and liquified sub- 
stratum will find vent, not along the line of greatest accumula- 
tion, but eed the outskirts of the basin. Thus in eastern Can- 
ada it is not along the chain of the Notre Dame mountains, but 
on the northwest side of it that we meet with the great outbursts 
of trachyte and dolerite, whose composition and distribution we 
— elsewhere described (Report of. Bobet Survey for 
1858, and Am. Jour. Science, [2,] xxix, 2 
The North American oe from ine grand simplicity of 
its geological structure, and from the absence, over gréat areas, 
of the more psig Gcianttods offers peeuliar facilities for the 
solution of some of the great problems of geology; and we can- 
not finish ren 2 article without congratulating ourselves upon the 
great progress in this direction which has been made within the 
last few years by the labors of American geologists. 
Montreal, March Ist, 1861. 
SCIENTIFIC INTELLIGENCE, a 
I, PHYSICS AND CHEMISTRY. : 
Pursics. sear’ 
1, On Regelation.—In the year 1850, Prof. Faraday directed Aine’ at 
tention of scientists to the remarkable fact that two pieces of moist 1¢e 
when placed in contact will unite, even when the surrounding tempera- 
ture is above 0° C. To the phenomenon in question the term “ regela- 
tion,” has been applied by Tyndall, who has made the fact above men- — 
tioned the basis of a theory of the plasticity of ice, in accounting for the 
descent of glaciers. Several theories have been advanced to explain nthe 
facts of regelation. Faraday* explained it by assuming that a particle “of 
water can retain its fluid condition only when in contact with ice on one 
side, but freezes when touched by ice on both sides, the general tempera- 
ture remaining the same. This explanation—with all deference be it said 
—is simply a re-statement of the fact and not an assignment of a phy 
ical cause. Person maintains that the solution of ice is a gradual pr 
contact with it; that a film of plastic ice or viscid water lies between the 
heat i 
ice and the water, and that is constantly passing from the water to : 
- Researches in Chemistry and Physics, pp. 373, 378. 
4 ae 
