of its former position, it is at present become a spacious strand, extending along that coast. Some few towers, indeed, and the strength of its walls for a time endured the whole force of the earthquake, and resisted the violence of its shocks; but scarcely had its poor inhabitants begun to recover from the horror of the first fright which the dreadful ruin and devastation had occasioned there, (and how great that was is not to be known,) when suddenly the sea began to swell, either through the impulsive force which the earth by its violent agitation impressed upon it, and thereby keeping up for a time, in one vast body, mountains of water,-or by what other means natural philosophers may please to assign, which on these occasions are the causes of its elevation- and swelling rose to such a prodigious degree, and with so mighty a compression, that on falling from the height it had attained, (although Callao stood above it on an eminence which, however imperceivable, yet continues still increasing all the way to Lima,) it rushed furiously forward, and overflowed with so vast a deluge of water its ancient bounds, that foundering the greater part of the ships which were at anchor in the port, and elevating the rest of them above the height of the walls and towers, drove them on and left them on dry ground, far beyond the town; at the same time it tore up from the foundation everything that was in it of houses and buildings, excepting only the two great gates, and here and there some small fragment of the walls themselves, which as registers of the calamity are still to be seen among the ruins and the waters, a dreadful monument of what they were.

"In this raging flood were drowned all the inhabitants of the place, who at that time might amount to near 5000 persons, of all ages, sexes, and conditions, according to the most exact calculation that can be made," &c. &c.

"There were twenty-three ships, great and small, at anchor in the port at the time of the earthquake: and of these, as has been mentioned before, some were stranded, being four in number, viz. the San Firmin', man of war, which was found in the low ground of the upper Chacara, the part opposite to the place where she rode at anchor, and near her the 'St. Antonio,' belonging to Don Thomas Costa, a new ship just arrived from Guayaquil: the vessel of Don Adirar Corsi rested on the spot where before stood the hospital of St. John, and the ship Succour' of Don Juan Baquixano, which had just arrived that very evening with a cargo from Chile, was thrown up towards the mountains, both one and the other of them at great distances from the sea; and all the rest were foundered."

Ulloa adds, that "this terrible inundation extended to other ports of the coast, as Cavallos and Guanape, and the

towns of Chancay, Guara, and the valleys Della Barranca, Sape, and Patevilca underwent the same fate as the city of Lima."

Five years afterwards, in 1751, on the 26th of May, the city of Conception, called by the Indians Penco, on the coast of Chile, was totally destroyed by an inundation of the sea; in consequence of which the inhabitants removed to some distance from it, and rebuilt their city on the spot where it now stands.

In Molina's account of Chile, speaking of this event, he mentions that the city was again inundated, alluding to a similar catastrophe which had befallen it some years before, in 1730 to which Ulloa has more particularly alluded. He says, on that occasion (in 1730) "the sea ut first retired a considerable way; but soon it rose so greatly that, passing its ordinary bounds, it inundated the city (Penco) and the country about it, obliging all the inhabitants to seek safety on the neighbouring hills."

The earthquake wave which overwhelmed Conception in 1751, was equally felt at the island of Juan Fernandez. I have a manuscript report of the Viceroy of Peru (lately published in the Journal of the Royal Geographical Society), wherein it is stated that "the first colony of the Spaniards had not long been settled there when it was almost totally destroyed by the same dreadful earthquake which, in the year 1751, overthrew the city of Conception in Chile: with the earthquake the sea rose and overwhelmed the houses, most of which had unfortunately been built along the shore. Thirty-five persons perished from this calamitous event, and amongst them the governor with his wife and children."

It is unnecessary for me to repeat, that in the great earthquake of 1822, on which there has been so much discussion, the sea is said to have been agitated in an extraordinary degree. Mrs. Graham, in her Journal, tells us that "on the night of the 19th of November, during the first great shock, the sea in Valparaiso Bay rose suddenly, and as suddenly retired, in an extraordinary manner, and in about a quarter of an hour seemed to have recovered its equilibrium."

She further mentions having heard from the officers on board Lord Cochrane's ship, that when His Lordship" and others threw themselves immediately into a boat to go to the assistance, if help were still possible, of the sufferers, the rushing wave landed them higher than any boat had been before, and they then saw it retire frightfully, and leave many of the launches and other small vessels dry.'

I had written so far when the accounts reached this counThird Series. Vol. 8. No. 46. March 1836.

X

try of the dreadful earthquake which, on the 20th of February last, again utterly destroyed the city of Conception, with its sea-port at Talcahuano, and all the towns of Chile between the parallels of 35° and 38° south latitude.

The details which have as yet reached us afford another remarkable evidence of the direful and irresistible effects of the earthquake wave. In the Bay of Talcahuano the sea is said to have risen three times, overwhelming the town, and sweeping away its ruins with such a rush and whirl of waters as, to quote one account, it is more easy to imagine than describe, and carrying some of the ships far up upon the shore.

The circumstance of a vessel, "the Glemalier," having experienced a violent shock when at a distance of ninety-five miles from the coast, which stopped her course and induced the master to believe she had struck the ground, coincides remarkably with old Wafer's account of what happened to himself off the coast of Peru during the earthquake of 1687, and is of value, in as much as it corroborates his testimony to a fact which before seemed hardly credible*.

Such is the list with which history furnishes us of these terrific inundations. Fearful as it is, if we bear in mind how recently we have become aware even of the existence of those coasts, and how extremely imperfect is our knowledge of them at all, we shall have no difficulty in believing that it comprises but a very small portion, indeed, of a series of events which, in a very short period of time, geologically speaking, must have left indelible marks of their tremendous agency, attesting but too well the calamitous visitations to which the inhabitants of those shores are subject.

XXXIV. Note on the Transmission of Radiant Heat. By the Rev. BADEN POWELL, M.A., F.R.S., Savilian Professor of Geometry, Oxford.†

FEW

EW scientific discussions are more unsatisfactory than those in which writers endeavour to point out, or explain, misconceptions of each other's meaning. In reference to one or two remarks somewhat of this nature made in the course of papers in recent Numbers of this Journal, on the subject of radiant heat, I will merely state, in the fewest possible words,

We believe that several if not many other instances of the same fact have been recorded, chiefly in the older accounts and collections respecting earthquakes.-EDIT.

+ Communicated by the Author.

distinctly what my meaning was, and there leave the ques

tion.

The result which I obtained in 1825, and which M. Melloni has so fully verified, was this: The effect from a luminous hot body, without any screen, upon a black and a white surface respectively, was observed to be in a certain ratio; the same effects when a transparent screen was interposed were in a different and greater ratio. M. Melloni's theory is, that this new and different relation to surfaces is communicated to the rays by, and in, the act of passing through the screen; so at least I understand it. Now this is what I objected to as a very singular theory, discordant (as I conceive) with all analogy, and needless, in as much as the effect is explained by the much simpler supposition, that there are two distinct sorts of heat emanating at the same time from the luminous body, distinct in their relations to surfaces as well as to screens.

It was to this single point alone that my remarks applied. With the other valuable results of M. Melloni I am not now concerned. I will merely add, in the present unformed state of this entire branch of our knowledge it seems hardly safe to adopt any theory, except as a mere conjectural guide. But I have the greatest hopes that before long we shall be in a condition to advance to some satisfactory general principles, when I find such an instrument as M. Melloni's in active employment in the hands of such able and zealous experimenters as are now engaged with it in Edinburgh and Dublin.

XXXV. On Sir G. S. Mackenzie's Remarks on certain Points in Meteorology, &c., inserted in Lond. and Edinb. Phil. Mag. for November 1835. By JOSEPH ATKINSON, Esq., Secretary to the Carlisle Literary and Philosophical Society.

I

To the Editors of the Philosophical Magazine and Journal. GENTLEMEN,

HAVE been induced by Sir G. S. Mackenzie's remarks on the equinoctial gales, contained in your Magazine for November last, to look for a corroboration of his supposition that the equinoctial gales have of late come from the eastward, but I cannot find that such has been the case here. The situation of Coul is most probably the cause of the easterly winds being so prevalent there. On the 22nd of September, which is the day mentioned as the one on which he wrote his letter, while an easterly wind was blowing, I find a southerly wind noted in my journal. This of itself is enough to show

that locality has a great deal to do with the kind of winds prevalent at each place. On the 30th of September, in the present year, the easterly winds began to below here, and continued without intermission till the 8th of October; and from the 26th of August to the 2nd of September, easterly winds also prevailed: but while these winds were altogether light, scarcely approaching to the character of a breeze, the westerly winds, which prevailed from the 2nd to the 29th of September, were very strong, and on several days, especially on the 28th of September, might be called gales.

Sir G. Mackenzie's remarks as to the easterly winds having lately come much charged with moisture will, I find on reference to my journal, apply to Carlisle as well as Coul; for on looking back at those days on which easterly winds have prevailed during the past year, I find a great proportion noted as drizzly or showery.

I have also remarked that easterly winds have become much more prevalent here of late years than was wont to be the case, while the south-westerly have of late been decreasing in number. Whether this excess of easterly winds is likely to continue, or will only be for a year or two, it is of course almost impossible to tell, but I am inclined to think it only temporary. It is rather remarkable that in the month of February last (1835) the wind never blew from an easterly point for even a quarter of a day. The month of May seems to be the one in which easterly winds have most prevailed here for the last two years.

The observations which are made at the Apartments of the Royal Society in London must surely be very loosely taken, for I often find the height of the thermometer as noted at 3 P.M., to exceed the maximum! This most probably arises from the use of two thermometers, having either different scales, or else hanging in different positions. This circumstance, added to the evidently too small quantity of rain which used to be given as the results of the observation of the raingauge (but which have lately been seemingly better attended to), shake the faith of the meteorologist in any of the observations published under the sanction of the Royal Society. Surely there ought to be one maker appointed to construct every instrument used by Societies, whether Royal or not, and by those who, living at a distance from towns, would still wish to compare their observations with those of others. The great attention which is now paid to meteorology as a branch of science demands that something should be done to secure the agreement of all instruments used by observers of the weather. Several pages of some scientific Journal should