HAIL, HAILSTONES, HAILSTORMS. 



HAIL, HAILSTONES, HAILSTORMS. 



i dull now proceed to describe, another and diattoet 

 form of aliui nihtrtf ice u produced, termed HAIL. 



Sir John Henehrl has Btated his views of the philosophy of thin 

 subject in the following terme : after relating the observation, during 

 a ballooo aeoent, of the temperature of 46* Fahr. at the height of 

 li,000 feet, and that of 22' only, or 94 colder, at the same eleration 

 la the deeoent, a heavy fall of now being then and there in progress, 

 he says : " It U evident that thu aroee from the condensation of 

 vapour at that level, and that, from the intrusion of come current, a 

 man of intensely cold air had been introduced, which, finding vapour 

 near saturation, converted it into mow. It is equally evident," he 

 continuea, " that had the latter condition prevailed, not at the level in 

 question, bat at a somewhat higher, where the condensation might 

 have been into rai very near the freezing point, the drops in de- 

 scending would have been frozen solid, and fallen aa hail. It might 

 have been ao equally, had the precipitation been so copious as to allow 

 the coalescence of a great number of minute particles in a nascent 

 state into drops frozen together inxtanter, since there is good reason to 

 believe that the solid form is never assumed without transition through 

 the liquid, however momentary. [*] The generation of hail seems always 

 to depend on some such very sudden introduction of an extremely cold 

 current of air into the bosom of a quiescent, nearly saturated mass. 

 Hailstorms are always purely local phenomena, and never last long. 

 They often mark their course by linear tracks of devastation, of great 

 length and very small breadth. In the hailstorm of July 13, 1788, 

 which passed across France from south to north, two such tracks were 



marked, of 175 and' 200 leagues in length respectively, parallel to each 

 other, the one four leagues broad, the other two, and separated by a 

 tract five leagues in breadth in which only rain fell. A similar 

 character is very common, though not to such an extent. Such linear 

 hailstorms are always attended with violent wind, sudden depression 

 of the barometer, indicating a great commotion in the air, and probable 



mingling of saturated masses of very different temperature 



Great hailstorms are often preceded by a loud clattering and clashing 

 sound, indicating the hurtling together of masses of ice in the air. 

 The recent experiments of [Professor Faraday and] Professor Tyndall 

 on the re-uniting of broken ice by ' regelation,' or a sort of welding, 

 fully explain the formation, under such circumstances, of large masses 

 f irregular forms in this aerial conflict." (Mttrarolnyy, ' Kia-yc. 

 Brit.' vol. xiv.) 



The following account, extracted from the celebrated ' Climate of 

 London,' by Mr. Luke Howard, F.H.S., of a hailstorm as observed at 

 Plaistow, in the county of Emex, near the metropolis (the scene of his 

 first series of meteorological observations), on the 19th of April, 1S09, 

 affords an instructive example of the local, phenomena of such storms : 

 "The day had been sultry, like some preceding ones, and overcast 

 with clouds, which during the afternoon gave evident demonstrations 

 of an approaching discharge of electricity. Large and deep rumnl-i- 

 $trnti were ranged side by side, mingled with the rirro-cuwiM/iMand 

 eirro*trattu, the whole having that peculiar, almost indescribable 

 character, which thexe charged conductors assume when wrought up to 

 the highest state of electric tetuim. About five in the afternoon, 

 being at the laboratory, and perceiving a continued roll of thunder, 

 with vivid lightning approaching from the south, and the appearance 

 of a heavy shower in that quarter, I anticipated a storm of no common 

 violence. We were proceeding to take measures for the safety of some 

 glass utensils, when in an in* taut there opened upon us a volley of 

 hail of such tremendous force, as in ten, or at most fifteen minutes, 

 demolished most part of the skylights and south windows in the 

 neighbourhood. These try buHlett, some of them a full inch in diameter, 

 were discharged almost horizontally from a cloud to the windward, and 

 in such quantity as to be drifted in large masses under the walls. 

 Whether borne by the impetuous blast that came with them, or 

 carrying the air thus before them, I could not determine, but such 

 was the velocity of their motion that in many instances a clear round 

 hole was left in the glass they pierced ; and one large pane (which 1 

 saw) had two such perforations distinctly formed, the glass otherwise 

 whole. The water in the river, lashed by the hail and raised by the 

 wind, resembled a cauldron boiling violently, rather than waves with 

 breakers. The electrical discharge* were incessant, approaching with 

 the cloud and passing off with it : .... This sudden irruption over, 

 it rained for a while moderately. The wind was at first K., then S. 

 during the bail, then W., then K., then W. again. About seven, the 



clouds all at once put off their stormy character The remainder 



of the evening was calm and pleasant. A person who was on the road 

 from Lmdun in It'nt (probably not two miles off) during the storm, 

 informed me that he experienced nothing but continued thnmli-r ami 

 lightning, and rrry hfary rain, the latter appearing luminous on the 

 ground on each side of him, which it often does in heavy storms. U 

 was evident from other circumstances that the hail was bounded in a 

 western direction by the village of Bow, and it reached eastward from 

 thence only about three miles. Its course appears to have been from 

 S. to N., over Hlackheath, Bromley, Plaistow, West Ham, and so up 

 the country between the rivers Lea and Roding." The amount of 



[ On lhl tubjert t* s piprr by Mr. Bnyfejr, On the probable fxl.Umce of 

 but two HMtei of AflfrtfitloB la Fmdmbl. Matter,- AnnaU of Pbilwwpby, 

 (tor SsBtsutor, l16,) voL ill. pp. m-200.] 



Umage occasioned by the hail in this cue is mentioned in the equal 

 at this article. 



HUT other account* of hailstorms, and remarkable falls of hail, 

 and of hailstones of remarkable character, at various periods, in 

 England and other countries, are distributed through the Climate of 

 London.' 



In the article ' Hail, 1 in Brande's Dictionary of Literature, Science, 

 and Art,' it is stated that " Hail usually precedes storms of rain, some- 

 times accompanies, but never or very rarely follows them, especially if 

 the rain is of any duration. The time of its continuance is always 

 very abort, generally only a few minutes, and very seldom so long as a 

 quarter of an hour." The writer of the article referred to further 

 remarks, that " the clouds from which hail is precipitated appear to be 

 of very considerable extent and depth, inasmuch as they produce a 

 great obscurity. It has been remarked,' he adds, " that they have a 

 peculiar gray or reddish colour, and that their lower surfaces present 



indentations." Other characters of these clouds have just been 

 noticed. 



Single hailstones have generally a crystalline structure, radiating 

 from a centre if large, forming spherical, oval, or rounded masses, often 

 marked out (on making a section,) into concentric layers, like the rings 

 in the section of the trunk or branch of a tree. The form is often 

 conical, with a rounded base, when they appear to consist of fibres 

 meeting at the apex, but there is reason to believe that these are 

 portions of sjiheroidal concentric-laminar concretions. They fall from 

 the size of small peas, or much less, to that of an egg, an orange, or a 

 man's head, and weighing from a few grains up to fourteen poun. . 

 upwards. Very frequently hail falls of which each separat. 

 originally was, a regular tetrahedral crystal of ice, generally with < 

 faces, apparently owing to the tendency of crystals belonging 

 monometric system of crystallisation to which ice in part belongs, to 

 assume curved forms. Often, these have an obvious concentric-! , 

 structure, and they are often degraded into a conical fonn by their 

 solid angles and edges becoming rounded by partial melting during 

 their fall. Some large hailstones of concentric structure have a 

 tetrahedral nucleus, the polyhedral having been gradually converted 

 during accretion into a spheroidal solid. As indicated above, the con- 

 centric-laminar is also a fibrous structure in hail as in beematito and 

 other terrestrial minerals. In the ' British Mineralogy ' of the late 

 eminent naturalist-draughtsman James Sowerby, a work through 

 are scattered m.iny valuable facts, is an excellent plate of a mass of 

 tetrahedral hailstones, with separate figures of the constituent crystals 

 and their structure. Sir J. Hervchel has cited from Dr. Thomson's 

 ' Introduction to Meteorology ' a remarkable example of large hail- 

 stones of a radiated structure, but such* as to evince that the particular 

 stone examined had been formed in passing through two distinct 

 regions of condensation in the air. He also cites from Dr. 

 the observation that in India the hailstones are from five to twenty 

 times larger than the average magnitude of those in England, often 

 weighing from six ounces to a pound, being seldom less than walnuts 

 in size, often as large as oranges and pumpkins. The storms in which 

 they are produced are almost always accompanied by viol, nt wind 

 and rain, thunder and lightning, and are frequent in the delta 

 Ganges, especially in the low country within fifty miles of the Bay 

 of Bengal. 



Herschel, also, after alluding, as above, to the effect of regela- 

 tion in producing masses of ice in the air by the consolidation of 

 aggregated hailstones, remarks, that " such are recorded to have fallen 

 of almost fabulous magnitude," of which, but with great caution, he 

 proceeds to recite several examples. The effect of the process of 

 regelation (or to adopt the recent correction of Professor James 

 Thomson, of that o/ mritlng and rrgdalion) in converting congeries of 

 hailstones into masses of ice is indubitable, but, we are in need of 

 sufficiently authenticated statements of the actual fall of such masses. 

 We appear not to have any account of such a phenomenon by a 

 qualified observer, and it is to be believed that in many instances a mass 

 of ice really produced on the ground by the consolidation of hailstones 

 which have fallen within a small area and heaped one upon another, 

 has been supposed to have actually fallen ready formed. The following 

 case from Dr. J. D. Hooker's ' Himalayan Journals' will illustrate the 

 view now taken. On the 20th of March, 1849, at noon, a violent 

 liailstorm coming from the south-west, occurred in the Terni, or damp 

 forest-tree region, intervening between the plains of India and the 

 Himalaya mountain*, in this locality the Sikkim Himalaya. The hail 

 was of "a strange form, the stones being sections [sectors or segments] 

 ipf hollow spheres, half an inch across and upwards, formed of cones 

 with truncated apices and convex bases," aggregated witli thrir bases 

 outwards. The fall of the large masses was followed by a shower of 

 the separate conical pieces, and that by heavy rain. ' On the mountains 

 this storm was most severe : the stones lay at Dorjiling [of which place 

 the mean temperature in March is 46" Fahr.] for seven days, congealed 

 into mames of ice several feet long and a foot thick, in sheltered 

 places. At Purneah, fifty miles south, stones one and two inches across 

 fell, probably an whole spheres." Mr. Howard quotes a notice of a 

 hailstone fallen in Hungary in 1808, which is stated to have exceeded 

 the strength of eight men to lift it. This, he remarks, recognising 

 (as far back as 1838) the fact as well as the principle of what i now 



