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Show 164 CHYMISTRV. again, the snuff of a candle. The " rival lustre" (only it is a dead one, and wants the "speculation" of the other), is charcoal, and nothing but charcoal. To the unreflecting, it may seem very wonderful,( if not altogether incredible, that marble palaces, and loaves of bread, and blooming roses, and clean hands, and eloquent tongues, and smiling faces, should all . be made, and made with equal ease, out of burnt sticks. But such parties should consider whose workincr they are thinking of; and then the whole become0s as simple as it is true. And, if the patience of any reader, not accustomed to think on such subjects shall have carried him thus far, we have no doubt that he will find in their " airy passage" from old to new, and from death to life, enough to make him wonder why he has not been an observer of nature all the days of his life ; and, perchance, he may regret that he has not. But there is no need for regret ; that only wastes time, all:d ma~es bad worse in all cases where we suffer It to mtrude. There is plenty of time still, if it were well appli~d; and there stands at the porch of nature no snarlmg Cerberus, with his three heads, all wrong ones, and his " confusion of tongues." How this singular action of matter in the state of air is carried on in all cases, so as to produce the endless variety that we see in nature, we cannot of course know · but we do know the results of it in many instanc~s, and that knowledge is the f~undation of nine-tenths of those arts by the practice of which we get our food, our clothing, and all our ac ... commodations and comforts. Men have "groped their way" to some. portion ?f that knowledge ; but. it is only since the m~roducho~ of mo~~rn or pneumatic chymistry, that IS, the science of the secrets of airs " that it has been followed as a regular science': and when we think of gas-lights, and steamboats and ten thousand other things that we i'Osscss in 'consequence of it, we cannot be too HEAT AND AIR. 165 grateful to those who made and applied the discoveries to which we owe these. And we have this to eH.courage us in the matter, that th~ whole is the result of observation-of that observatiOn of nature which is far more open to us than it was to those men, for they have left us the.ir keys. . . But if the aerial state of thmgs be, as 1t certamly is the real and only state in which nature acts, then the atmosphere must necessarily be the general theatre of nature's acting. Nor is there any doubt that it is. There are, indeed, some operations which could not be carried on in the atmosphere, because some of the materials would be dissipated by that; and there are others in which all the materials would go off together. Thus we can get. t~e water out of brine, and leave the salt, or the spint out of wash, and leave the water, by boiling in the open air; but we must be contented to lose the water in the one case, and the spirit in the other. Nor have we any means by which we can, in the open air, and by boiling, get out the salt and leave the water, or the water and leave the spirit. In like manner, we may in an .open fire drive the charcoal and the bitumen out of ' common coal, and leave the clay and the iron with 'which coal is sometimes mixed; but we cannot, in an open fire, refine the coal by taking out the iron and clay. Every change that we make in the heat of any thing, the atmosphere affects that thing in a different manner ; and it is the same whether the change be produced by nature or by art, or whether it take place in the atmosphere, or in that which is exposed to the atmosphere. Only, we must bear in mind that the atmosphere and the object act differ- / ently; and thus the effect of heating the atmosphere is the same as that of cooling the object, and that of heating the object is the same as cooling the atmosphere. The perfect mobility of the atmosphere is one of its most striking and its most useful properties. |
