$3 General Reflections on Heat: 
chinery of the natural world were adjusted oa eameceers to 
support this equilibrium of temperature. jut this happy 
adjustment was by no means accidental; we can even see 
the springs by which it is effected. 
In the first place, heat manifests the strongest tendency to 
diffuse itself in every direction. Let us concentrate it in 
any given spot, and it flies off with inappreciable velocity ; 
and, unless the intensity be ae by constant additions 
of heat, that spot or body shortly becomes reduced to the 
same temperature with Ristcianlian bodies. Upon this agent 
itself, therefore, is impressed a character, that — the 
violence which it seems constantly prone to exe 
the second place, the ain, by its elasiny, affords the 
means of conveying off all excesses of heat. This cause 
operates in maintaining the — of temperature on a 
most extensive scale ee its action, at one time, in 
gentle gales and breezes; i ane in the northern blast; 
at another, in dreadful hurricanes, that sweep around this 
solid ball. All these, whatever partial evils they nivalis 
contribute to this grand benevolent design; to eep ‘t the 
element of fire within its own narrow ds. 
In the third place, the vast collections of water, which 
cover so great a part of the rae furnish another means of 
regulating the temperature of the earth. So happily does it 
conduce to this object, that were the art of navigation still 
unknown, we might fancy that lakes and seas and oceans, 
were made on yh to be reservoirs of heat in winter, 
and fountains of cool breezes in summer. The multiform 
changes of state which water undergoes, including congela- 
4on and liquefaction, evaporation and condensation, are all 
made subservient to the same end. These operations are 
the special barriers which Providence has set on the terres- 
trial part of the globe to check sudden excesses of heat and 
cold; and few instances of the proofs of intelligent =e 
the works of creation, among all those happy illustrat 
which Dr. Paley has collected, everstruck me as: more con 
vineing than these. On the approach of a cold night, it is 
pleasing to watch the thermometer: and note the progress of 
its descent, oe sudden change of weather has caught 
the mercury ata high degree. You may see it descend 
rapidly to the freezing point; and, were you unaccusiomed 
‘o the result, you might imagine that a most terrible frost was 
‘-hand. But the mercury no sooner reaches the «freezing 
