General Reflections on Hedi. et 
point than its course is suddenly checked; congelation 
itself is made to contribute a portion of heat. sufficient to 
mitigate the severity of the impending frost; and hours, in- 
stead of minutes, are occupied in carrying the mercury 
through a few degrees below. In like manner, it is pleasing 
to remark, how retarded are its movements, as it approaches 
the extremes of heat. A hot day is passing over our heads, 
although, as often happens, the morning was cool and tem- 
perate. In two hours, perhaps, we have seen the thermome- 
ter rise from 50 to 80 degrees. Will the heat of two hours 
carry it forward 30 degrees more to 110? Experience alone 
could ensure us against the approach of such a consuming 
fire. But what prevents it? The evaporation of water from 
the entire surface of the earth, is now set on foot, with hur- 
ried progress, hastening its speed as the heat increases, until 
it brings to a stand the furious element. 
By these mutual agencies of evaporation and condensa- 
tion, of congelation and liquefaction, the excesses of heat and 
cold, to which the temperature of the surface of the earth is 
alternately prone, are so nicely balanced, that, among many 
thousand degrees that lie between the known extremes of 
heat and cold, the whole range of natural temperature is only 
30 or 100 degrees. Pleasant and delightful as is this little 
space in the vast scale of temperature, where all animals so 
securely dwell, and where the flowers of spring bud and 
blossom and the fruits of autumn are matured, still it lies, 
like a small island in a sandy desert, between two regions of 
desolation and death, which seem about to blast it, on the 
one hand, with withering frosts, or to consume it, on the 
other, with devouring fire. The causes which we have just 
enumerated are those effectual barriers that Omnipotence 
has placed, to guard this blooming animated spot against the 
dangers that encompass it. And among all the innumerable 
causes thatare continually at work to disturb this equilibrium 
of temperature, we may rest assured that no essential irregu- 
larity will occur, until, in the sublime language of Young, 
‘“* All the formidable sons of fire, 
Eruptions, earthquakes, comets, lightnings, play 
Their various engines ; all at once disgorge 
Their blazing magazines, and take by storm’ 
This pure terrestrial citadel of man.” 
Vor. X.--No. ft, 12. 
