“1. The body of the gale usually comprises an area of rain or foul weather, together with another, and, perhaps equal, or greater, area of fair or bright weather.” (Am. Jour. of Science, vol. xlii. p. 114.)
Now, in the first place, we must distinguish between a storm and fair weather, before we can tell what the former is, and it is difficult to assent to a theory which explains what a S. E. storm of twelve hours’ continuance is, by including two or three days of succeeding N. W. fair weather wind, as a part of it. There is no proportionate relation as to time, nor any relation as to qualities, or the attending conditions of the atmosphere, nor any conceivable connection, except the hypothetical one of gyration, between the two winds.
And, in the second place, it is true, and Mr. Redfield is well aware of the fact, that winds often blow for many days from the N. E., S. W., or N. W., without any preceding or succeeding winds to which they have any discoverable relation. If, therefore, truth would justify Mr. Redfield in including the fair weather wind, a difficulty would remain which his theory does not cover or explain.
No American, except Mr. Redfield, has been able to discover satisfactory evidence of the gyration of storms, by actual careful observation, or a careful unbiased collation of the observation of others. Professor Coffin is reported to have read to the Scientific Association, at their Buffalo meeting, a paper, confirmatory, in part, but I have not been able to see it. The tracks of tornados have been searched as with candles. When they have been narrow, from forty to eighty rods, their action has been substantially similar, and, although, as we have herein before stated, some irregularities have been found which were consistent with gyration—for irregularities attend the violent action of all forces, and particularly the motion of electricity through the atmosphere, as every one who has seen the zig-zag course of a flash of lightning knows—yet the evidence of two lateral inward currents, or lines of force, has predominated over all others. In all cases, where the path is narrow, those lateral currents are the actors; they constitute the tornado; their irregularities of action produce the exceptions; but the exceptions are neither numerous nor uniform, and do not prove either the theory of Mr. Espy or that of Mr. Redfield. The action is not that of moving air, merely, but of a power exceeding in force that of powder, which nothing but electricity or magnetism can exert. As the path widens, the wind becomes more like the straight-line gust which follows beneath the ordinary severe thunder-showers. His theory finds no substantial confirmation or support in the path of the tornado.
Several storms were investigated by Professor Espy, some of them the same which Mr. Redfield had attempted to show were of a rotary character; one or two by the Franklin Institute of Philadelphia; one by Professor Loomis, already alluded to; and recently, two by Lieutenant Porter, from logs returned to the National Observatory. None of these investigations confirm the theory of Mr. Redfield. Indeed, Mr. Redfield himself has found it necessary to resort to suppositions of modifying causes to explain the evident inconsistencies. It is assumed that the axis, or center, oscillates, and describes a series of circles; and thus, one class of difficulties is avoided. Again, it is assumed that simultaneous storms converge and blend upon the same field, and another class of difficulties are surmounted. And, again, inasmuch as it is notorious that violent gales are rarely if ever felt with equal violence around the area of a circle, but from one or two points only, it is assumed, that the storm winds ascend, superimpose, and descend again, when they return to the place of their first violent action, etc. The simple truth requires no such resort to modifying hypothesis.
Still, another objection is, that the changes in the barometer, which occur before, during, and after storms, do not sustain the claims of Mr. Redfield or the requirements of his theory.
The barometer sometimes rises before storms. It generally commences falling about the time, or soon after the storm sets in, continues to fall during its progress, and rises again, sooner or later, afterward. This is the general rule.
On this subject Mr. Redfield’s claim is this:
“Effect of the Gale’s Rotation on the Barometer.—The extraordinary fall of the mercury in the barometer, which takes place in gales or tempests, has attracted attention since the earliest use of this instrument by meteorologists. But I am not aware that the principal cause of this depression had ever been pointed out, previously to my first publication in this journal, in April, 1831, when I took the occasion to notice this result as being obviously due to the centrifugal force of the revolving motion found in the body of the storm.
“Since that period, inquiries have been continued by meteorologists in regard to the periodical and other fluctuations of the barometer, and the relations of these fluctuations to temperature and aqueous vapor. But these incidental causes of variation, in the atmospheric pressure, prove to be of minor influence, and we are left to the sufficient and only satisfactory solution of this marked phenomenon which is found in the centrifugal force of rotation.”