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PROCEEDINGS OF LEARNED SOCIETIES.
NEDICAL SOCIETY OF LONDOX. panying their beginning and progress, as THE Medical Society of London have well as the effects by which they are ge
I recently published the first volume Herally followed. of their Transactions, containing many Could my pen equal my sensations, I interesting articles, and among others should be able to paint their effects in the following: On the Land Winds of the most lively colours, aided by eighs Coromandel, and their Causes, by Wile years experience in a country the most liam Roxburgh, M.D.
noted on the Coast,* for their intensity, The land-winds on the coast of Coro. Tue land.winds are preceded in the mandel, says Dr. Roxburgh, are those latter end of March, or in the beginning hot wiirds which blow at a particular of April, by whirlwinds, which belueen season of the year and hour of the day, eleven and twelve o'clock at noon, hurry from the western hills, commonly called in various directions, niostly froin nese the Ghauts, towards the bay of Bengal. to east, towards the sea. These are In the more inland countries, as above called by the natives Peshasbs or Devris, the Ghauts, they are not confined to any because they sometimes do a little mise regularity, though they are felt sometimes chief to the lighter buildings. with a great degree of severity, and for About the same time, or a little after bours together.
the appearance of the wifirlwinds, we I understand also, that in the upper may observe all ranges of bilis garoished parts of Bengal, they are sometimes ex, as it were with clouds, which become perienced very severely; but whether daily darker and heavier, until they dis. from the west or the northward, or in charge themselves with much thunder what part of the year, I have not been and lightning in a heavy shower of rain able to ascertain. As far as this only After this inarked phænomenon, the lends to prove the insufficiency of the land winds set in immediately with all denomination, it would signify little, the violence of which they are capable. although in other respects it would be of Their commencement is generally in more momente
the latter end of April, or beginning of As they are generally supposed to be Dlay, and their reigo lasts to the earlier peculiar to this country, and are felt days of June, during which period they during several months in the year, we generally exert their violence from ten should imagine their laistory and causes or eleven o'clock in the morning, until to have been perfecily investigated and about three or four o'clock in the after. understood; but, I know not why, nei noon. ther the one wor the other has as yet In this season, the atmosphere is combeen satisfactorily explained.
moniy hazy and thick, except that in the The most plausible reason generally evenings and nights, the sky is serene given for the great accumulation of heat and clear, provided the land- winds do an them, is the heat of the season in not continue the whole day. which they prevail, and the long tract of The rising sun wbich portends a landcountry over which they have to pass. wind day, appears of a fiery red, and as That this, however, is not the true cause, if involved in mnist, which mist is changed it shall be my endeavour to demonstrate; afterwards into clouds that lie heavy on to which I will add an attempt to point the Ghauts, out the most probable one, founded on The land-wind of each day is almost known chemical principles.
always preceded by a long calm, and inkespecting the theory I have to offer, mediately by a cloud of dust. I regret bat it las found but few patrons. Their diurnal violence is terminated in this country, which, however, I flatter along the coast about two or three myself, may be ascribed more to the o'clock, by the setting-in of the sea-breeze manner in which it has been proposed, which wafts delight and health as far as than to the foundation on which it is its intluence extends, which is not inore constructed,
than ten or twelve miles inland. An In order to facilitate the explanation abateinont of their intensity from thence of my sentiments, as well as to show that to the Ghauts, is all that can be hoped the land-winds really deserve some at- for, tention from the philosopher, I shall briefly recount the planomena accom Samulcotah, in the Northern Circars.
The The sea-breeze regularly begins in the cially on those bills on which the bam. afternoon, at one or two o'clock, blowing boos grow very thick, which has proba. pretty steadily until sun-set, when it dies bly led the natives to explain this phaaway gradually, and at sun-rise it is again nomenon so rationally, by ascribing it to perceptible, though weakly.
the friction of these bushes against each When I say its influence is only felt other. ten miles inland, I do not wish to be un Lieutenant Kater, of bis Majesty's derstuod that it does not extend further: 12b regiment, thinks that the corky bark I mean only its powerful refreshing pro. of the adenantheru pavonina, is often perties, which it loses in proportion to spontaneously inflamed, as he has frethe distance from the sea, and in an in- quently found, on his surveys, ils baik. verse ratio to its strength, which is not converted into charcoal, and several of great. In general, it arrives at thirry these trees burnt down to the roots, ale miles distance from the sea, in the evene though they were not in the vicinity of ing, and is then only agreeable by the any other trees. ventilation it effectuates.
In Europe, I know these spontaneous . In the country above the Ghauts, as in ignitions have been much discredited; Alysore, the east wind prevails also in and I doubt not, but should these few the afternoon, but from a period much sheets ever be published, many objec. earlier, or cotemporaneous with the sea. tions will be raised against what I have breeze on the coast, which renders it related: but I have endeavoured to state clear that this inland breeze either does facts only, which a luxuriant imagination not extend further than to the Ghauts, or might have painted in more striking really originates there; a point which colours, but I am sure not with stricter deserves to be ascertained, as another adherence to truth. phænomenon depends upon this ciicum- The land-winds are noted for the drystance.
ness which they generally produce on Should the sea-breeze fail, as some- the face of the country, as well as on times happens, the land-wind decreases that of the animal creation. This sengradually until it dies away in the begin- sation is particularly felt in the eyelids, ning of the night, which, on account of which become in some measure quite its calmness, is dismal to a degree: next stiff and painful. This is owing to the morning, a lice motion of the air is immediate volatilization of all humids again perceptible, but at the usual time that irrigate our organs, and which, in the wind sets in as strong and hot as the this particular one, probably gives rise day before. Every thing we put our to inflammations of the eyes, so frequent, hands upon is then distressing to the at this time of the year. * touch, which inust be the case when the The continuance of this wind causes temperature of the body is inferior to pain in the bones, and a general lassithat of the atmosphere. This we ex- tude, in all that live; and in some, para. perienced for almost a fortnight in the lyric or hemiplectic affections. Its sud. year. 1799, in the Northern Circars, den approach has, besides, the dreadful when the thermometer, at eight o'clock effect of destroying men and animals in- . in the night, stood at 108°, and at noon stantaneously. at 1120. Shades, globes, tumblers, then It is very common to see large kites very often crack and break to pieces, and or crows, as they fly, drop down dead; the wooden furniture warps and shrinks and smaller birds I have known to die, so much, that even the nails fall out of or take refuge in houses, in such num. doors and tables, &c. In their greatest bers, that a very nunerous family has intensity, however, I have never seen the used nothing else for their daily meals thermometer rise higher than 1159, viz. than these victims of the inclemency of in the coolest part of the house, though the season and their inhospitality. In posome say they have observed it at 1300. pulous places it is also not very uncom
The Ghauis, and the hills at no great distance from them, are then seen lighted
* The eye-fies, so often supposed to ocall night by spontaneous fires, and often
casion it, produce a transient and sharp pain in a very picturesque manner.
in the eye, but never, I believe, a lasting ina These illuminations appear, in general, flammation. It is generally thought infece about the middle of the mountains, and tious, and may be so by the interference of seldom or never extend to the top or the eye-fies carrying the contagious matter bottom of them. They take place espe- from an affected eye to a sound one.
non to bear. that four or five people* led to an investigation of the causes that have died in the streets in the course of produce them. Before this can be done, a day, in conseq!!ence of being taken un- however, I must prove, according to proprepared. This happens especially at mise, that the theory of our philosophers the first setting-in of those winds.
is founded in error. The natives use no other means of se- They ascribe, as already observed, the - euring themselves against this wind, but extraordinary heat which distinguishos
shutting up their houses, and bathing in these winds from most others, to the the morning and evening; Europeans absorption of caloric, in their passage cool it through wetted tatst made of over an extensive tract of country, at a straw or grass, sometimes of the roots of time when the sun acts most powerfully the wattie,t which, wetted, exhale a in our latitudes. pleasant but faint smell. It will be ins According to this theory, the heat credible to those that have never wit should increase in proportion to the nessed it, but the evaporation is really space over which this wind is to travel; so great, that several people must be it should be botter on the coast than it is kepi constantly throwing water upon the at any part of the country inland, or, tats (eight feet by four) in order to have which is the same, it should decrease by the desired effect of cooling a small degrees froin the eastern to the western room.
sea of the peninsula. Experience, howIt would be scarcely necessary to ob.
ever, teaches us the reverse ; for it is serve, if it were not in contradiction to hottest near the Ghauts, and among the public opinion, that the cold produced is valleys between those ranges of bills, not a peculiar property of the wind, but than at any place on the coast; and the depends upon the general principle, that heat of those winds decreases also as all liquide Bassing into an aèriform state, they approach the Bay of Bengal, and in absorb heat, and cause immediately a direct ratio from the Ghauts to the around them a diminution of it, and con sea: accordingly, it is at Ambore* hotsequently a relative coldness. On the ter than at Vellore,f and at this place same principle depends also the cooling again than at Arcot,f Conjeveram,ll and of wine and water, in the land-wind
in the land-wind Madras, where the land-winds are scla seasons, the latter in light earthen ves. dom felt with any degree of severity. sels, which allow an oozing of the water Time is another measure applicable to through their pores, and the former in the acquisition of heat, as it increases to bottles, wrapped in a piece of cloth, or the greatest pitch which a body is cain straw, which must be constantly kept pable of receiving in proportion to its moistened.
continuance: the land winds should The great violence of these winds is at therefore be cooler when they set-in at last terminated by frequent slowers of ten or eleven o'clock, and hottest at their zain, in June; in the low countries, and termination in the afternoon; they should by the greater quantity of the regular be so at least at noon, when the sun is rains falling in the joland countries, nearly vertical, and has the greatest ine which seem to suspend the partial for fluence on the substances from which mation of clouds along the Ghauts, and heat is to be attracted. The contrary, to leave them clearer, and visible at a however, comes nearest to the truth; for greater distance, than they had been at it is known that these winds set-in with any other period of the year before. their greatest violence and heat at once,
After the enumeration of so many dis. agreeable circumstances, I am naturally love
* A place situated in the most western val. any ley of the Ghauts, immediately at the foot
of the steepest ascent into the Mysore # Four people dropped down dead' at Ya• country. mam in the year 1797, an hour after my ar Lies in a spacious valley, nearly at the tival there from Masulipatam: and at Samul- entrance of the Ghaut mountains, and has Cotah, four or five died the same day on the the advantage of an open communication with short road between that place and Peddapore : the flat country to the north-east. the number of inhabitants of either of these I A large city, the capital of the nabobs places does not exceed, I believe, five thous of the Carnatic, east of the ranges of bills sand,
called the Ghauts. The frame of them is made of bamboos, ..., miles east of the latter place in the in the form of the opening in the house to be road to Madras, a large populous place. I tatted, let it be door or window, which is have chosen this tract, or line, as the most then covered with straw in the manner every known, although not the hottest ; for Ellore, one thinks best suited to retain the water Rajahmundry, and Samulcotah, in the North. longest.
ern Circars, are by far more exposed to these I Andropogon muricatum.
winds. MONTULI Mag. No, 209,
which rather abate than increase, as at a time when beavy clouds darkened might be expected.
the western hemisphere. We should, on this principle, further Further, in the inonths of March and suppose the heat would increase gra- April 1804, we had ofien at Bengalore, dually with the return of the sun to our in the afternoons, strong gusts of wiad latitudes, from its southern declination, from the eastward, which, in common, and stand always in proportion to its po- were styled land-winds, and were really sition. We find, however, that expe. as hot and disagreeable as moderate land. rience also contradicts this point of the winds are in the Carnatic. I could theory under discussion; for after the have multiplied instances of this kind, sun has passed our zenith, the land- but am of opinion that in a fact so much winds set-in at once with all their inten. known, it would be perfectly needless. sity, in the manner before described, and The last refuge of the defenders of they cease as abruptly before its return this theory, is the valleys of the Ghauts, ayain.t
in which they pretend the heat is geneA material change in the temperature rated by the concentrated and reflected · of this climate is certainly effected by rays of ihe sun.
the approach of the sun from the soutli; I will not deny but the heat occasioned but the beat which is thus caused, and by these causes, may contribute much to · which increases by imperceptible de raise the heat of the land-winds; but the
grees, is never so great, and is only felt · sudden appearance of the latter, their by those who expose themselves to it une usual strength, and abrupt disappear. protected; for the air remains propor. ance, all militate against that explanation tionally cool, and our houses afford, in as a principal cause, this season, a pleasant retreat. We find The heat of these winds should in this it far otherwise io a land-wind; for this case, to say a few words more on the penetrates our inmost recesses, and rene preceding subject, decrease regularly ders life miserable every where.
from the point where it is greatest 10I have before observed, that winds wards the opposite, on both sides, as is equally hot with those of periodical du- the case on the coast of Coromandel. ration, are felt in all parts of the country, On the contrary, we find that, iminedia and at different seasons; a circumstance ately on our having ascended the Ghauts, alone suficient, if proved, to overthrow or on the top of hills* elevated above the the ground-work of the old theory. : clouds, we have escaped their heat all at
For a confirmation of this, I will ap. once. It is hereby remarkable, that peal to the general observation, that in the direction of the wind remains to ap. mediately before a long rain the weather penrance nearly the same every where. is sultry, and that a single shower is al. In Mysore, for example, the wind is, in ways preceded by a warm disagreeable the land-wind season, west during the wind.
greater part of the day; in the afternoon We are very particularly reminded of it is from the east, and comnionly warıner the approaching great monsoon in Oc. iban the former, tober, by the oppressive heat we have in. This, together with what had been the calm evenings of that month, which, said before, will, I hope, be thought suf. I am persuaded, would equal that of the ficient to establish my opinion relative laud-winds in May, if the atmosphere were not cooled in the latter part of the night by breezes that have wafted over
* Major Lambton, at the top of Carnati. extensive inundated plains,
ghur, one of the higbest hills in the CarI can reter, secondly, to my Meteoro
natic, about three thousand two hundred fece
0. above the level of the sea, found, in the midlogical Journal, according to which, the dle of the land-wind season, the thermo. 4th of June 1800, at Madavaram, a meter at 79o and 80° in the mornings, and place not far from Bengalore, the ther- at noon 820 and 84o, when it was below ac mometer rose for a short time to 104° 103, and inore. This observation may be just before a slight shower of rain, and the more depended upon, as the Major rea
mained for a considerable time on the top + The sun is in the zenith at Madras of this hill, in the pursuance of his most about the 26th of April.
accurate survey, in the course of which he + The sun is again in our zenith on its pays great attention to this, as well as to all souchern declination about the 19th of Aue other points that could influence his learned gust.
to what cannot be the cause of the heat in this season. At times, we have also in the land-winds.
: showers from the east and south-east, It remains now to point out a theory and my attention shall not be wanting supported on a firmer basis, which I to ascertain whether it is not at the time shall endeavour to do in the following when the land winds blow hottest in the pages. It is founded on a chemical Carnatic. By this we see, that the principle, and will explain, I think, the clouds formed on the Ghauts, charged heat of these winds in a satisfactory with water and electricity (by causes I manner
am not now to investigate), are drawn to The principle itself needs no demon- the westward, whilst the heat, which dustration, as it is admitted as a general ring the formation of these clouds, must law; viz. that “all bodies, when they necessarily be discharged, is carried to become more dense, suffer heat to the east or to the lower parts of the coast, escape; or, what is the same, they give and causes the properties for which the out hear." For example, when gases or land winds are so remarkable. seriform substances becoine vapours, I have acknowledged already, that the they discharge as much heat as was ne heat occasioned by the power of the sun cessary to keep them in their former in this season, contributes to the aggregaseous state: further, vapours in con- gate of it in the wind; but I must observe densing into fluids are known to do the also, that it acts only as a secondary sare, as also fluids acquiring solidity. cause, and passively, by preventing its
I am sorry that the quantity of leat absorption and diminution in the career Det free in the condensation of vapours over a variety of substances, particularly required for a pound of water, has escaped moisture, with which it would combine, my meinory; but I recollect it was very if they had not been previously removed considerable. We know, however, that or incapacitated. a great deal of it is required for the eva. In colder climates, this absorption poration of the same measure, and it is takes place in a greater degree, as subbut reasonable to adınit that the same stances are abundant with which the heat quantity with which it has combined produced by the formation of rain can should be discharged on its returning to combine and become inperceptible.t its former state of fluidity.
It is, however, there also often remarked, In order to apply this principle to ex. that the heat of the sun in a cloudy day plain the presence of heat in our land- is more powerful than at any other time. winds, I must first observe, that the at. In common this is ascribed to the reflec.. mosphere in January, February, and tion of the rays, of the sun from the March, is perfectly clear and serene; and clouds; but I opine it is often the conse. then I will call to mind what has been quence of the formation of water in the said of the phænomena of those winds, clouds, which obscure the sky at that that they are preceded by clouds on and moment. among the Ghauts, and that a heavy It has been observed, that the heat of shower of min from that quarter an- the land winds is not felt on tbe top of nounces their arrival; that during their high hills, or on plains of a very inconsicontinuance clouds are observed to lie on derable perpendicular height above those the Ghauts; and that the atmosphere, in which it rages most violently; as, for tren in the low country, is hazy and example, in Mysore near the Ghauts, thick, I must add also, that the coun., which is only about five hundred feet Iries west of the Ghauts are at this sea- higher than the valleys immediately beson frequently visited by heavy showers low. This might be considered a weighty of rain, accompanied with much thunder objection against my theory; as heat, and lightning, and sometimes with hail, considered in the light of an elastic fluid, Here in the Mysore country I have found expands equally on all sides; and from the heaviest showers of this kind to come whatever cause it proceeds, it should be from the north-west, * which is exactly supposed to extend even further where in the direction of the countries remark- it ineets with less resistance, as from the able for the great heat of the land-winds
* Earl Dundonald's Treatise, p. 20, “The The hottest land-winds in this season frequent changes in the degree of heat and (1804) at Madras, were, I understand, from cold in the atmosphere are to be ascribed more the north-west; which corresponds with the to the alternate disengagement and fixation direction from which the rains came in My- of heat by chemical combinagiou, than to the Scre at that period.
effects of the solas rays."