HAIL, HAILSTONES, HAILSTORMS. 



HAIL, HAILSTONES, HAILSTORMS. 



606 



termed regelation, was doubtless " what is called ' an ice-board ' 

 formed by hail agglutinated in a hollow, by partial fusion on the 

 surface, the whole freezing again by the intense cold within." The 

 largest hailstones are stated to be of very nigged and irregular form, 

 resembling portions of a great sheet of ice broken into pieces. An 

 American observer, the Rev. D. A. Clark, cited in the ' Climate of 

 London,' saw in the heat of summer, hailstones about one-fourth or 

 three-eighths of an inch thick, and of sufficient diameter to hide a 

 shilling, almost every one of which was perforated in the middle, as 

 if it had been held between the fingers till thus melted. When the 

 perforation was not complete, there was in every case a tendency to it. 

 These were probably of the concentric spheroidal laminar structure, in 

 which the central portions were incomplete. Mr. Howard has him- 

 self described a freezing shower which fell at Plaistow on the 19th of 

 January, 1808, and which glazed the windows, and encrusted the 

 walls, and encased the trees, the garments of passengers, and the 

 plumage of birds. A portion being received on a sheet of paper was 

 found to consist of hollow spherules of ice, filled with water; of 

 transparent globules of hail, and of drops of water at the point of 

 freezing, which became solid on touching the bodies they fell upon. 

 As it is stated that the thermometer exposed from the windows 

 indicated S0'5, the temperature of these drops must have been below 

 the freezing point, their solidification taking place, agreeably to the 

 property of water in that condition, on the agitation of their particles 

 occasioned by their impact on the surface upon which they fell. 

 Had the process of freezing proceeded further before the fall of the 

 shower the hollow spherules filled with water would have become 

 ordinary hailstones with a cavity in the centre. 



The electrical character of showers of hail has already been alluded 

 to, and is well exemplified by the following account, given by Mr. 

 Howard, of one which fell, with many others, in different parts of 

 England, on the 19th of April, 1807, at Plaistow. Being carefully 

 examined throughout, it presented the following phenomena : When 

 the cloud discharging it of course a nimbm [CLOUD] " was on the 

 horizon, N.E., and the shower behind it, the pith-balls of the insulated 

 electrical conductor [of Mr. Howard's fixed apparatus for investigating 

 the electricity of the atmosphere] remained in contact. When the 

 extremity of the upper surface of the inverted cone of cloud had 

 arrived in the zenith, they opened negative, and diverged slowly to full 

 two inches, at which time pretty strong sparks were drawn from the 

 conductor. During the remainder of the approach of the shower, they 

 gradually closed again. At the moment when the latter [the shower] 

 began to touch the observatory, they opened pomtive, diverged more 

 speedily, and the apparatus gave strong sparks for a considerable time 

 potitire. As the cloud drew off to the S.W. this change gradually 

 ceased, and the balls opened again iieyatire, diverging gradually as 

 before, then converging, and lastly were left a little charged positive." 

 In all this, as Mr. Howard points out, we see the natural effects of the 

 high positive charge in the column of falling hail, which may probably 

 have been six or seven miles in diameter, and which appeared to be 

 surrounded with a negative area, extending into the dry atmosphere 

 about three miles in every direction. This very considerable quantity 

 of electricity, and that of some intensity, was conveyed by an amount 

 of hail comparatively insignificant; for when melted into the rain-gauge, 

 together with that of several previous showers, it did not produce more 

 than a hundredth of an inch of water in depth. It is an example of the 

 fact we shall have to consider elsewhere, of how powerful an electrical 

 charge ice is capable of receiving. 



Saussure, as cited by Mr. Howard, attributed the greater or less 

 prevalence of hailstorms in particular localities of the Alps to the 

 relation of their electricity to that of the neighbouring mountains, the 

 clouds or storms being either attracted or repelled by them, according 

 as the electricity is similar or opposed to that of the mountains. Borgo 

 Franco, in Piedmont, he had been informed, was peculiarly subject to 

 the calamity of hailstorms ; and it has often been observed, he states, 

 that in other plains bordering on high mountains, at a certain distance 

 from the mountains, hail is much more frequent than in places that lie 

 somewhat nearer or more remote. There are distances, too, Sau.s.-uru 

 adds, that seem privileged, where hail very seldom falls. On an estate 

 on the river Arve, not quite half-a-league from the foot of Mount 

 SalSve, there had not been within the memory of man any considerable 

 fall of hail, the stormy clouds passing always nearer to the mountain 

 or at a greater distance from them. 



Arago (' Meteorological Essays,' transl. into English, pp. 106-108) 

 mentions some instances in which the aqueous precipitations from the 

 atmosphere during thunderstorms, whether liquid or solid, have been 

 observed to be luminous, one of which is the luminous rain during a 

 hailstorm already cited from the ' Climate of London.' Among them 

 is one recorded by Lampadius, who was informed by some miners at 

 Freyberg that the small hail which fell during a thunderstorm on the 

 25th of January, 1822, was luminous when it reached the ground. 

 These cages are doubtless to be explained by the high electrical charge 

 which everything acquires during some thunderstorms ; there are 

 experiment* with electrical apparatus in which corresponding luminous 

 phenomena are occasioned. 



The practice appears to have originated in the last century of 

 making fires on the ground, and of discharging artillery and otherwise 

 exploding gunpowder, on the approach of storms, for the purpose of 



dissipating them, and especially of preventing the formation or the fall 

 of hail. Arago (loc. cit. pp. 212-218) has given an account of this 

 practice, of the efficacy of which he considers that there is no sufficient 

 evidence, if even the tendency of the evidence is not to show that con- 

 tinuous discharges of artillery may induce local thunderstorms. On 

 the other hand, the experience of the Marquis de Chevriers, in pre- 

 serving his lands from the ravages of hailstorms by the explosion of 

 boxes of gunpowder, which he caused to be fired on the neighbouring 

 heights on the approach of a storm, while the villages in the vicinity 

 frequently experienced their baneful effects, does not appear to have 

 been sufficiently considered by that philosopher. There are some 

 grounds for believing, also, that the particular conditions of the atmos- 

 phere which result in the formation of hail may be counteracted by 

 fires. Matteucci, the eminent Italian physicist, whose electrical 

 researches continue to enrich science, informed Arago that there is 

 a parish near Cesena, in ^omagna, throughout the extent of which, 

 for seven miles round, the peasants, by the curd's advice, place at about 

 every 50 feet heaps of stone and brushwood, which they set on fire 

 when a storm is seen approaching. This practice had been in force for 

 three years, during which time the parish had not suffered either from 

 thunderstorms or from hail, although it formerly suffered much every 

 year from hail, and the neighbouring parishes had continued to do so 

 during the period. " Three years," Arago remarks, however, " are not 

 a sufficiently long period of time to allow of any definitive conclusion 

 as to the preserving influence of large fires. The experiment is 

 being continued, and the public will not fail to be informed of the 

 results." 



The principle of insurance has been applied to indemnify persons for 

 the very heavy losses sometimes occasioned by these meteorological 

 phenomena, both by the Royal Farmers' and General Insurance Insti- 

 tution and by a society connected with the Norwich Union Insurance 

 Company. The uncertainty which exists in reference to the occur- 

 rence of these frequently calamitous storms in any particular locality, 

 and the circumstance that, while no human sagacity can foresee or 

 prevent them, it is utterly impossible to produce them by fraud, appear 

 to render such casualties peculiarly fit, so soon as observation and 

 experience shall have established accurately the average risk, for the 

 application of a principle which has long been applied to casualties of a 

 nature less uncertain, more easily provided against, .and which afford 

 greater opportunities for deceit and imposition. The Hail-storm 

 Insurance societies have published chronological lists of the most 

 remarkable hailstorms in this country during the present century, 

 which present an array of destructive calamities far exceeding what 

 might have been expected from their rarity. It is curious also to 

 observe that they appear to have increased in frequency of late years. 

 In one case, which we select solely from the more circumstantial way 

 in which the details are given, many farms of corn were (on the 14th of 

 July, 1824) literally destroyed in Hertfordshire,_Middlesex, and Essex'; 

 the damage done upon a space of 3487 acres in the last-mentioned 

 county alone was estimated at 14,574^., or about 41. 3 Id. per acre, 

 upon an average. It is stated that this was the third time within a 

 period of thirty years that the crops in the north-western part of that 

 county had been destroyed in like way. During the great hail-storms 

 in the months of July and August, 1843, by which immense damage 

 was done in Cambridgeshire, Norfolk, Suffolk, Essex, Hertfordshire, 

 Berkshire, Kent, Oxfordshire, Bedfordshire, Gloucestershire, and York- 

 shire, several cases of individual loss amounted to upwards of 2000Z. 

 The breakage of glass in windows and skylights, and more especially in 

 conservatories and hothouses, is one of the most frequent injuries 

 inflicted by hail-storms, the masses of ice which fall being some- 

 times sufficient to demolish the wooden framework also. Such extra- 

 ordinary cases of devastation will be fully accounted for if it be 

 considered that, as it is stated in a paper issued by the Farmers' 

 Insurance Institution, on the authority of Leslie's ' Elements,' " hail- 

 stones having a diameter of two inches," a size which has been 

 exceeded in several well-authenticated cases, " will fall with a velocity 

 of 1134 feet in a second, or more than \\ mile in a minute." In the 

 hail-storm of the 19th of May, 1809, Mr. Howard's account of which 

 has been given above, it is estimated that 200,000 panes of glass were 

 broken in the immediate vicinity of London alone, besides great 

 damage being done in fields and gardens, and the foliage and branches 

 of trees being cut off. An equal number of panes is supposed to have 

 been broken in the northern suburbs of the metropolis on the 30th of 

 July, 1 826. In the denser parts of the metropolis itself less damage 

 appears to be done on such occasions, probably because the vast column 

 of heated air always rising from it alters the local atmospheric con- 

 dition requisite for the production of large hail. 



Hailstones of from six to eight or nine inches in circumference are 

 frequently mentioned as having fallen in this country, in the lists 

 referred to, which are compiled from contemporary publications ; and 

 on the 3rd of August, 1824, when the ea-tern part of Suffolk was 

 visited by a violent hail-storm, by which fowls and game, as well as 

 glass and crops, were extensively destroyed, the ice accumulated in 

 some places to a surprising depth. In many cases a considerable extent 

 of ground has been covered to the thickness of several inches. It is 

 worthy of remark how very large a proportion of the destructive 

 storms are recorded to have occurred in the months of June and July. 

 Without noticing the cases in which two or more storms which occurred 



