A REMARKABLE FROST.

Thames Star, Volume X, Issue 3292, 10 July 1879, Page 2

A REMARKABLE FROST.

A frost of a most disastrously destructive character visited France oti'thtf 2&d of last January,, and from the 'sirijfaW conditions pf this phenomenon 7 ahd';ihe wide-spread devastation it,c^us6<f^t mems some .special atJt^nfion; see that this peculiar yisifattqn^jthijiiprg strong >light,,<?n. some noticeable jJo^dji^iyis connected with the freezing, q|, Mjtpr and the laws of heat. Jt will also show what a slight change "in the meteorological state of the atmosphere mKfprdinee'&.e most widespread and p utildoked • for

.In the early "part of the month of January—we' abridge the interesting narrative giren in a late issue of the iterue dcs Deux ~Mon£es'-^3ai<ge3^ ; snqw had fallen, and. the passage, oL-this through the atmosphere Had no doubt swept the air of all impurities, and left^it peculiarly clear aqd transparent. About the middle of the 22nd of January, while the air was quite calm, a very fine rain ca I Wl^ifli«fat ;|^v oontjaj^ ?r W jr ery cold. The extreme coldness of the rain attracted the attention of observers, who, on testingit*found that.the,ipin was from three to six degrees (Reaumur) below the freezing point nw^gw? jhj|^s a singularity which deserves' consideration. In the ordinary state of things water at this temperaturej^eJ^w tbfi&e,esngsojnt is converted into ice, and the rain becomes hail. This rain, however,, was free from everyi adm^tpm tf ie^ m&b&Pfap* perfectly liquid. This circumstance has to be borne in mind in attempting to ex* plain the,{ condition^t, j.whwh I Althoughi the rain was liquid*while falling through the air, directly it touched the ground it spread QU^in^a^^dpaHeat of ice, brilliant and smooth as varnish, and and so slippery that men and animals had great difficulty to k*ep^m|a)to| O If —states the account we are following— the matter had rested here, this would have been but tho)€trdinafjyrglase*fn}st seen every winter. But "what gave fee oig* tinctive character to this one was, that this frozen* ;glaze ;i was^ equally, on trees, on branches and leaves, on tele* graph wires, on umbrellas, on clothing, on .the windows,of jcarriages—not ioude, but outside—on all olbjects; efen ontfiose that were warm. The rain continued all the 23nd, during the night, andtjyu.lt of the following day. 'A's it tellm^rozen stratum continued to thicken till it attained unheard- ( of. A proportions. The ice thus formed in no respect resembled the ordinary rime frost formed by the congeailragV <oti Taptour i*eplo(ait«a;a» dew. It was a smooth rounded ice, quite transparent and moist. The quantity deposiited was enormous. A telegraph wire- was; covered with 18 'times'Uti own weight of ice, a branch of rhododendron with? fs®\ i: times its weight, most of the ice lying on the upper . side'- of., the object. The consequence was that telegraphs were broken down and forest trees stcipp.ed.and uprooted by the immense accretions. During the stillness of the night,'white the cold, cruel rain was silently falling, constant reports could be heord in i wooded district as the forest trees" were broken oft' or uprooted, and came crash* ing down, literally crushed by tbe^qad piled upon them. Animals came'jjn ib? their share' of this , pitiless" destruction* Ground-larks were actually fro?e# to; the, soil by their feet or tail. In Champagne partridges were seen frozen, embedded in a winding sheet of transparent. ideY';V{lt was impossible," writes M. Jamirij ** to avoid comparing this glaoiKl enshrouding with that which in early geologic epochs surprised the mastodons which are found at the present, day ourtbo-bjifckstot the Lena. These, also, are f<Mnd»tand* ing ', the nose pointeds .tt)>\in ilhe «ifc,U enclosed in a vestment of ice, not of snow, as though ihoy had been surprised by an

immense glaze frost. This hypothesis is fes plausible as that of the frozen whirl wind which has been imagined as explanation of their entombment." Tho

urea of tornst country that was more or loss ruined and destroyed by this terrible frost must have been immense, judging

from the statistics given, which relate only to tluvzobe of Paris. It is sufficient to say that the foi'ests of Franco suffered injury to an extent that will require the growth of generations to repair.

The scientific question involved is, what were the meteorological conditions to which these extraordinary and unprecedented results were due. We can only

briefly indicate the lending lines of tho. explanation.< Most readers who have pjiid any attention to the laws of heat as /exhibited in the process of freezing know i that to melt a given quantity of ice as ,!much beat is absorbed as would raise the

temperature of that quantity of water ** 80deg. (Keaumur.) Inversely, in the ( freezing of water which has been brought I down to the freezing point, the abstraction of the equivalent of one degree of heat results in the solidification into ioe of the 80th part of the volumo of water. The abstraction of another degree equivalent results in the freezing of attothejtf 80th, and so on till the whole is Frozen. Could, however, this water be kept from freezing, and the process of heat abstraction bo carried on till the temperature of 80deR. below freezing ' point was reached, and then congelation be allowed, the result would be the instantaneous transformation of the liquid Water into solid ice at the ordinary temperature of freezing point. Now, as a fact, experimenters have succeeded in keeping water liquid several degrees below the freezing point by preserving it, as the cooling process went on, from all shake or disturbance. But any sudden,

shock had the effect of at once precipita-

tingihe change, and producing at any rate a partial congelation." The liquid condition thus maintained in presence of a degree- of cold more than sufficient to effect freezing is known as that of superfusion* -.('•■■ ■ ■ ,■■-'■ ;i. ' ■ After these preliminary considerations,, we can readily explain the causes to which the destructive glaze-frost of January last in France was owing. • "The rain had in some manner been cooled to several degrees below the freezing point. It would in the normal state of things have become frozen into hail, but from some unknown cause it retained its liquid form, and existed in the state of superfusion,

the shock it sustained by striking the

body on which it fell was sufficient to precipitate the instant change of a portion of the water into ice, the other at first remaining fluid, and perhaps afterwards freezing more slowly. Hencef" it was that it was on the upper side of the wires, branches, &c, that the greater portion of the ice was found attached. But, although this! manifestation of these conditions of afinoßphene superfusion was a rare one, it is probable that the condition often exists, and that we hare a familiar 'instance in the case of hail, the formation of which has never been clearly explained. But, however this may be, the circum-

stances of this extraordinary frost being

strongly before us how we exist at the mere; of slight and imperceptible changes in the condition of . the all-enveloping atmosphere in which we live and move.