Smoke is electrified _positively_, by the act of combustion; the earth and the adjacent atmosphere, when storms are gathering or approaching, is _negative_. Hence the smoke spreads, and is attracted downward by an opposite electricity. On the other hand, it is interesting to see, at other times, and when the difference in temperature is not material, but the whole atmosphere is positive, with what rapidity and compactness the smoke will ascend in a _straight and elevated column_ from the chimney, repelled by a similar electricity. I am aware it is generally supposed the smoke descends because the _air is lighter_. But it is a mistake. I have seen it descend when the barometer was at 30 deg..60, or .60 above the mean. There is, too, a draught downward in chimneys, in such cases when there is no smoke or fire in any of its flues. Thus Jenner says: "The soot falls down;" whether he meant by this that there was an actual fall of soot other than what is occasioned by the rain falling in through the chimney top, and disturbing the soot, as sometimes happens, I do not know. It occurs rarely, and is of very little practical importance. But every housewife knows that chimneys, which have been used in winter, and are full of soot, _smell_ before storms. The odor results from a downward draught and the dampness of the air. So the smoke from one flue will descend another, into some unused room, on such occasions. Another class of these electrical signs are felt by those who are suffering from chronic diseases, which have affected the nerves and made them sensitive. Thus Jenner: "Old Betty's joints are on the rack." And Hone adds: "Her corns with shooting pains torment her, And to her bed untimely send her." But Old Betty's rheumatism or corns are not alone in this. Those whose bones have been broken feel it. All invalids feel it. And, indeed, all observing healthy persons may, and do, although all are not distinctly conscious of it. It is common for such to say, I feel sleepy, or I feel dull, or, It _feels_ like snow, or _feels_ like rain, and thus from their own feelings to be able to predict, not only falling weather, but its _character_, whether snow or rain, at a time when either may occur consistently with appearances. This change is a change from the positive electricity which is so congenial to the active--"bracing" is the usual term--to negative and damp--for this change is accompanied by condensation, as I believe all changes from positive to negative are. Certain it is, if the atmosphere is highly charged with negative electricity, condensation takes place; if with positive, evaporation. Perhaps it is a change of the associated electricity which accompanies magnetism, and not of the free atmospheric electricity alone. Hence another phenomenon alluded to by Jenner: "The walls are damp, the ditches smell."