130 
TEMPERATURE AND METEOROLOGY. 
We lately described a house which, by the heating power of a chamber acti? 
upon air circulating within it and throughout the area of the building, became vA 
effectively warmed. Subsequently, an opportunity has occurred to examine anotlr 
erection constructed upon still better principles. This shall not be lost sight of, It 
in the meantime, while waiting for positive and conclusive evidence of facts, it y 1 
not be unprofitable to appeal to sound theoretic principles. 
1. It is a maxim, or law of physiological chemistry, as applied to aerial flui 
that each gas becomes a vacuum to every other gas : thus, if a vessel contain hydrog I, 
the lightest of all bodies that are known to possess weight, and a quantity of comm 
air, nitrogen, or oxygen be let into that vessel, the gas or gases so introduced vl 
pass interstitially through the particles of the hydrogen, without chemically unitit 
therewith, or requiring any additional space. We are indebted to the late I. 
Dalton for this most interesting discovery. 
2. Radiation is that species of action by which heated bodies communicate hjt 
to other bodies, or rather to air interposed between them; the power diminisls 
in geometric progression, according to distance. If a surface radiate heat, i 
intensity of that heat will be equal at equal distances, but it decreases, in inve s 
proportion, at unequal distances. How very irregular, therefore, must be the acti 
of all our present radiating surfaces. A flue, for instance, shall be almost r - 
hot at its entrance — six feet from that point its surface may not sustain I50 c i- 
and at the opposite end of the house, the hand shall scarcely detect any sens! 3 
warmth. Now, as heat diminishes in inverse progression — if, at two feet, 13 
radiated particles raise the mercury of a sensible thermometer 40°, the sa:3 
instrument, remaining exactly opposite the same part of the flue, but at four ft 
instead of two feet distance from it, will indicate an increase of 20° only — i. 4., 3 
3 : 40 : : 4 : 20. But when the whole surface loses heat at every foot of its cour, 
how infinitely complicated must be the sum of its radiating power. We stand i 
need of improvement ; and fortunate it is that the prospect brightens, and prorni: 3 
not to be delusive. — More of this at an early opportunity. 
Equability of heat is rendered more desirable by the accidents, which forme:/ 
were of frequent occurrence, with the old fire-flues; these, of course, ha) 
ceased where hot water has been substituted ; but some years since, a parcel f 
damp moss was laid on a flue near its entrance, nothing was apprehended, but i 
the morning, a strong, foetid, ammoniacal odour was detected, and on opening tj) 
house the moss was seen reduced to ash ; while vine and other leaves, at the remo 
end of the house, were completely decomposed and shrivelled, though no heat h i 
approached. An apparatus, to produce healthful warmth, must affect the air and t) 
air only, and operate by means of its interstitial diffusibility. 
