160 



THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



rouc^hish, and of a rosy blush, very different from that of the two African albinos s^-i^n 



and described by Voltaire, and quoted by Lawrence Journal of Asiatic Society of 



Bengal. 



METEOROLOGY. 



OBr.HRVATIONS OK THE EFFECTS OF A REMARKABLE StORM OR ToP.NADO. Bt 



Walter R. Johnson, A.M. Abridged fiom Vol. VII. of the Journal of the 

 Academy of Natural Sciences of Philadelphia, 



Considered as a meteorolo3;ical phenomenon, the calamity which, on the I9th of 

 June 1835, desolated a part of the city of New Brunswick in New Jersey, is worthy of 

 the most attentive investigation. All accounts concur in representing the air of the 

 morning, and, indeed, of the whole day up to the time of the tornado, as unusually 

 sultry. At four o'clock the sun was still unubscured at Princeton ; but within half 

 an hour, a cloud from the noith-west had reached that place, and a shower of rain, 

 accompanied by a brisk wind from the south-west, had commenced. Before five 

 o clock the rain tiad ceased, and the air was less oppressive. The evening continued 

 tranquil until ten o'clock, when another shower of rain fell, accompanied by some 

 w.nd ; but within half an hour the sky was once more cloudless, and the wind began 

 to rise with much force from the west or north-west. Between eleven and twelve 

 a sensible depression of the dew-point was noticed, as indicated by the action of the air 

 on the lungs, as well as on the surface of the body. From twelve at night to five the 

 ,n2Xt morning the wind was boisterous ; and a great change in the state of the atmos- 

 phere had obviously taken place. An electrical machine, which it had on the day pre- 

 vious been found impossible to excite, was, at nine or ten o'clock, a.m., able to yield 

 sparks an inch and a half or two inches long, between balls three-fourths of an inch 

 in diamett^r, a sure indication of an increased distance between the dew-point and the 

 temperature. 



Intelligence of the occurrence at New Brunswick having been received during the 

 forenoon, it was resolved to visit the spot, and endeavour to ascertain such facts as 

 might explain the mode of action of the tornado. On ai riving within six miles of the 

 city, we were informed that it had been seen about a mile and a half to the north- 

 east, and that the dense black cloud was, by the junior observers, conceived to be 

 filled with crows ; an appearance afterwards explained by the fact that shingles, boards, 

 &c., had been carried upward by the tempest from buildings destroyed in that vicinity. 

 On reaching the height about half a mile from the dense portion of the city, the first 

 buildings which had been damaged were passed. A barn had been completely demol- 

 ished, and most of the lighter materials scattered to a great distance. The house 

 was not thrown down, but left leaning with no part of the roof remaining, except 

 some of the rafters ; and the fact here witnessed was repeatedly observed in the town 

 below, where several houses within the path of the tornado were deprived of their 

 shingles, and the ribs which had held them to the rafters, but the latter still continu- 

 ing partially or entirely undisturbed. In a few cases, in which the ridge of abuildin'y 

 lay in a northerly and southerly position, the eastern slope of roof was observed to be 

 removed, or at least stripped of its shingles, while the western slope remained entire. 

 Many buildings were likewise observed with holes in their roDfs, whether shingled or 

 tiled, but otherwise not much damaged, unless by the demolition of windows. These 

 appearances clearly demonstrated the upward tendency of the forces by which they 

 were produced, while the half unroofed houses, already mentioned, prove that the re- 

 sult out of all the forces in action at the moment was not in a perpendicular to the 

 horizon, but inclined to the east. Such a force would apply to the western slope 

 of the roof some counteracting tendency, or relieve it from some portion of the up- 

 ward pressure. Had there been no other facts to shew the powerful rushing 

 of currents upward, the above would, it is conceived, have been sufficient to 

 settle the question, but 'taken in connection with the circumstance that roofs 

 so removed were carried to a great height, and their fragments distributed 

 over a large extent along the subsequent path of the storm — that beds and other 

 furniture were taken out of the upper stories of unroofed houses— that per- 

 sons were lifted from their feet, or dashed against walls ; and that, in one instance, a 

 lad, of eight or nine years old, was carried, upward and onward with the wind, a dis- 

 tance of several hundred yards ; and, particularly, that he afterwards descended in 

 safety, being prevented from a violent fall by the upward forces, within the range of 

 which he still continued. In connection with these and similar facts, it seems impos- 

 sible to doubt that the greatest violence of action was in an upward and easterly 

 direction. 



The next point to which attention was called by the appearances around, was the 

 manner in which this upward current had been supplied from below ; and for the so- 

 lution of this question, it was necessary to compare objects throughout the whole 

 breadth of the track left by the storm. A peach orchard on the slope of the hill de- 

 scending to the town, gave the first indication in regard to this matter, but the laro-er 

 fruit and ornamental trees, in some gardens in the neighbourhood, together with an 

 inspection of the forest on the east side of the river, shewed conclusively that on the 

 extreme borders of the track, the forces were nearly or quite at right an<^les to its 

 general direction. Uprooted trees along the southern border lay with their tops to- 

 ward? the north, those on the northern border to the south ; thus pointing to a com- 

 mon object in the central hne of the current. From the outer edges, however, towards 

 this central line, the trees were observed on both sides to have a gradually increasino- 

 inchnation towards the east, and in the middle to be entirely in thai, as a general di- 

 rection. None were seen with the tops from the centre of the path. A frame-build- 

 ing, which was on the southerly part of the track, was unroofed, and the remaining 

 part of the structure, with its contents, removed bodily three or four feet to the north- 

 ward. All the herbage, shrubs, and trees, in its immediate vicinity, and the trees in 

 a garden, were found lying with their heads in a northerly or north-easterly direction. 

 A stone near the river, and on the northern border of the path of the tornado, was 

 lifted from its foundation about four or five feet towards the south. A row of pop- 

 lars, which had been prostrated in the lower part of the city, and on the northern 

 part of the path, fell southward. Another evidence of lateral inward currents was 



found in the appearance of many forest trees, east of the river, which, though too far 

 removed from the central line of the path to be uprooted, were still so much within 

 the range of the lateral forces as to have their outside limbs, or those most remote 

 from the central line, broken off by the effect of cross strain ; while no similar frac- 

 ture was seen on limbs turned towards the centre of the path. This result will be 

 easily understood when we consider the well known difl'erence between breaking 

 a limb by cross strain, and that of drawing it asunder by simple longitudinal tension. 



Another fact, indicative of the direction of currents from the sides inward, was no- 

 ticed on the plain east from the Raritan, where the shingle and fragments of boards 

 lay with their longitudinal direction generally towards the point to which the storm 

 was moving, ft'lany of them were found far beyond the bolt of ground on which the 

 violence of the wind had been exerted. Their position may be explained by referring 

 to the three forces in action at the moment they reached the ground : — First, the 

 force of gravity, which, if the air had been motionless, and the bodies descending perr 

 pendicularly, would probably, from the unequal density of the parts of the several 

 masses, have caused most of them to descend endwise; and then the position, sub- 

 sequently taken by them respectively, would have been a matter of indifference, and 

 we might have expected to find them lying promiscuously. Biit, second, they were, 

 while in the air, moving onwards with the storm in an easterly direction, and when 

 the lower end struct the ground, the composition of this force with gravity would 

 naturally have thrown the centre of gravity over to the east, and we should have ex- 

 pected to find the lighter end of every piece of timber in that direction. But, third, 

 if a current of wind were encountered near the ground, running towards the centre of 

 the path, we should, on the north side of the path, expect to find the lighter ends 

 of each piece directed to the south-east, and on the south side to the north-east ; pre- 

 cisely what appeared to be the case, so far as could be judged from the general ap- 

 pearance of the masses. 



The next set of facts observed had reference to the course of the materials pro- 

 jected upwards after they had arrived at a considerable elevation. All accounts agree 

 that the appearance of the cloud vyas that of a funnel or inverted cone, with the apex 

 resting on the ground. The falling rafters, scantlings, and other parts of the ruined 

 buildings, generally indicated that they were, subsequently to the upward action, carried 

 outward by the gradual enlargement of the current into which they had been drawn. 

 The shingles and boards, just described, were cases in point, being found far beyond 

 the trail of the tornado as marked upon the surface. Rafters, which penetrated budd- 

 ings south of the track, entered them on the north side, and in a direction inclining to 

 the south-east. Their descent in some instances was with great violence, contrary 

 to what happened in the ravage of the upward motions; where a lad, already referred 

 to, was deposited in safety after an aerial journey of one-fourth of a mile. A window- 

 frame and brick wall were, in one instance, penetrated by a rafter twenty feet in 

 length, eight inches wide, and from four to six inches thick. In the passage of the 

 storm from the city to the opposite bank of the Raritan, no indications were, of course, 

 left to mark its action upon the vraters ; but it was stated that it had laid the bed of 

 the channel bare, and it is probable that had it traversed a great extent of water, it 

 would have assumed the character, as it certainly had the form, of a water-spout. 

 The upper edge of the opposite bank was marked by two well-defined stripes, each 

 from ten to twenty feet wide, and one hundred or more feet asunder. Here, it was 

 supposed, must have been the outer edge of the aerial trunk, or funnel, through which 

 the air rushed upwards, and as the tornado, in its onward movement, advanced against 

 the bank, the air coming in on every side to fill up the partial vacuum would exert 

 the greatest force at the moment when it changed its horizontal for a vertical motion. 

 The surface of the ground beyond this point seemed, in some places, to have been 

 raised, as if the air beneath, by its sudden rarefaction, had thrown up small portions 

 of the soil, which was rather dry and porous ; and it is perhaps worth consideration, 

 whether this cause may not, in this and similar occurrences, have facilitated the over- 

 turning of trees themselves. 



In conclusion, it may be remarked, that the directions and intensities of the forces 

 in this occurrence, together with the hygrometric states of the air, preceding and fol- 

 lowing the meteor, and the inverted conical form of the moving column, as confirmed 

 by several witnesses, not less than the fall of hall, and the distribution of frag- 

 ments of materials beyond the path of the ground current, seem most satisfactorily 

 accounted for, on the supposition that a disturbance of atmospheric equilibrium results 

 from a deposition of moisture in the higher regions of the atmosphere giving out a 

 great amount of latent heat, which, in turn, expands the cold dry air above the 

 forming cloud, and creates an ascending movement; the expansion of pure air by an 

 addition of heat, being in such cases much greater than the contraction of this at- 

 mospheric mixture by a condensation of its moisture. In this effect is, of course, in- 

 volved the well-known principle, that the capacity of air for heat is augmented as its 

 volume expands, but the increase of capacity for heat being less rapid than the supply 

 of heat from aqueous depositions, an ascending current is maintained with a force 

 due to the difference of these two causes. The origin of this view of the subject, 

 with which the writer had been made acquainted previously to the examination above 

 detailed, is due to Mr J. P. Espy. 



Fall of Meteoric Stones in Brazil, — On the 1 1th December 1836, about 

 half-past eleven o'clock, f.ji., the sky clear, and the wind south-west, a fire-ball, of 

 uncommon size and brilliancy, appeared over the village of Macoa, at the entrance of 

 the river Assu. It immediately burst with a loud crackling noise, and a shower of 

 stones fell within a circle of ten leagues. They fell through several houses, and 

 buried themselves some feet deep in the sand, but they did not occasion any further 

 damage than killing and maiming a few oxen. The weight of those picked up varied 

 from one to eighty pounds. — Poggendorf s Annalen. 



Edinburgh: Published for the Proprietor, at the Office, No, 13, Hill Street. 

 London: Smith, Elder, and Co., 65, Cornhill. Glasgow and the West of 

 Scotland: John Smith and Son; and John Macleod. Dublin: Georgk 

 YouKG. PARiS : J. B. Balliere, Ruede I'Ecole de Medecine, No. J3 bis. 



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