table matter, of which I spoke in my last letter, got to be dry enough to take fire.

The dry season of the present year we recognize only in the months of March and April and a part of January. From inquiry, I learn that well defined dry seasons have also been rather rare previous to my stay in the colony.

Table No. 4 gives the course of the clouds for seven months. The most numerous direction is as usual from south and east and the points intermediate amounting to 293. As a striking feature may be noticed the increase in the number of currents from the south since January, when there are only six, while in April we find 37 and in May 31. This may well account for the fact, which captains of vessels trading between the United States and the coast of Venezuela have noticed so frequently, of meeting during the months of April and May with steady blowing southern breezes, and which I had an opportunity to notice myself on my last voyage to Laguayra. In some places east of the colony, on the back of the Cordilleras of the coast, I have experienced this steady current from the south as often as I had occasion to traverse this region on my way to Caracas, with the exception of only once. It amounts sometimes to a strong breeze. Other colonists, who frequent this road more than I do, have noticed this remarkable wind nearly at all times of the year.

Several times I had a most excellent opportunity for observing and tracing the course of this southern current to a great distance in the direction south and north. I was then standing on the very crest of the mountains of the coast, having a view towards the north upon the sea, and towards the south over a part of the fertile valleys of Aragua. Scattered masses of clouds showed plainly by their motion the direc tion of the current in a long line, whence it came and whither it went. The annexed figure may serve to give a somewhat clearer idea. It is to represent a vertical section of the territory from south to north, a the place of observation, V the valleys between the northern and southern ranges, c c clouds moving with the eastern trade-winds towards the west, the line b d the track of the high southern current, which had a velocity of about twelve miles per hour, and a somewhat sinking tendency, until it struck the northern range, where it was forced upwards for a short distance until it reached the crest, and then went on unobstructed on the other side of the mountains, in a horizontal line, apparently lowering but very little, leaving hereby the eastern trade-winds of the sea far below and undisturbed in their regular and steady course, which is nearly at right angles to that of

the former. The lower clouds of the valleys showed plainly a motion from east to west, as seen against the dark background of the southern mountains. The high southern current was not indicated by clouds in those places where it was vertically over the lowest parts of the valley; but when drawing nearer to the Cordilleras, on which I stood, the vapors which it contained condensed rapidly, and became visible as drifting, incoherent clouds sweeping by, and which could still be seen on the sea-side as long as they floated over the dense primeval forest, which extends here from the mountains' tops to the very margin of the sea.

Here I may also remark that the great amount of cloudiness, which in some respects may be regarded as a disadvantage to observation, offers, with regard to the currents of the atmosphere, great advantages, the condensed vapors indicating the various motions and directions of these currents, and I have had, therefore, opportunities to observe them in most of their various forms. Sometimes I have seen the air ascend and descend vertically with considerable velocity, at other times pushed up the inclined planes of mountain flanks on one side until reaching the crest, and then gliding or flowing down on the other side somewhat like a liquid, following in its course the most depressed localities and ravines in all their windings. Sometimes the eastern currents may be seen in their gradually ascending but nearly horizontal course to meet the higher southern current at right angles, and, without mixing, to be deflected by the latter in a horizontal semicircle, or downward or upward, as the case may be. I have also seen two opposite currents meet, when each endeavored to force its antagonist back with alternate success and failure, until one got the better over the other, and at last kept undisputed sway.

At certain seasons of the year we may see extensive sheets of cloudy masses press closely over the northern or the southern range of the colony valley, and gliding down the declivity for a short distance become invisible and disappear in crossing the cultivated part of the valley, but reappear again on drawing near the opposite ridge. Frequently I have seen immense masses of clouds leaning against the northern side of the crest of the mountains, and as if stuck to them, for whole days, and while the base was gently sliding upwards towards the south, the top of the cloud, which was towering above the mountains, was bent back and moving slowly in an opposite direction.

When standing on some high mountain, especially early in the morning, I have seen dazzling white coherent masses of clouds filling up far below me whole valleys, the surface of these clouds representing immense and level snow fields, from which, in a most lovely and striking contrast, the green summits of the smaller mountains protruded as so many islets, or higher and lesser promontories of a frozen arm of the ocean. The delusion is sometimes most complete, and cannot be viewed without feelings of pleasure and surprise. The elevation of the upper surface of these clouds was between 5,000 and 6,000 feet above the level of the sea.

A striking feature in table No. 4 may be found in the prevalence of northern currents from November till February, inclusive, while they are much rarer or entirely wanting in March, April, and May.

Among the number of days free from clouds we find that at 2 p. m. throughout all the twelve months there was only one single day where the sky was entirely clear, but at 9 p. m. we had a clear sky on eightyeight days. In the month of September the sky was during all the ninety observations made in that month more or less clouded. At 2 p. m. the sky was entirely overcast on one hundred and thirty-five days. In May it was entirely overcast during forty-seven observations. The number of rainy days is two hundred and thirteen.

Table No. 5 contains observations on the motion of strata of clouds of different heights.

Observations on the motion of the highest clouds would be very important, but in this region we are unable to make a great number of such observations on account of the cloudy state of the sky, and we have to make the best of the few opportunities we may now and then get. As April is one of the most favorable months for this purpose, I have chosen this time, and have taken peculiar pains in collecting the facts contained in table No. 5. The greatest difficulty hereby exists in telling exactly which of the many different thin strata of clouds are the higher and which the lower ones. I was sometimes obliged to watch them for ten minutes right over head; but knowing that inaccurate observations are infinitely worse than none at all, I did not shun any inconvenience to arrive at the true motion of the different strata.

From this table we see that in the upper and highest regions the following winds were observed chiefly to occur: W.NW., W.SW., N.; in the middle regions, say from 7,000 to 9,000 feet above the sea, S.SE., W.SW., N.NW., N.NE.; and in the lower region, say from 7,000 down to 5,000 feet and still lower, S.SE., E., E.SE.

I may here remark that, from long continued observation on the motion of the clouds, I am inclined to believe that all the easterly winds of this region are gradually ascending in their course towards the west, while the southern as well as the western currents are gradually descending in their course.

Diagram No. 7 gives a view of the curve of mean monthly temperature for Colonia Tovar compared with the curves for New Orleans, St. Louis, Missouri, and Boothia Felix. I have chosen these three latter places because they are all North American, and lying nearly under one and the same degree of longitude, but in different latitudes; Boothia Felix in north latitude 70.2°.

Diagram No. 8 contains all the mean daily heights of the barometer from November 7, 1856, to April 30, 1857, and from May 9 to June 3. A similar diagram for June to October, 1856, I have sent already with one of my former letters. At that time I remarked that a kind of periodical rising and falling in periods from four to five days was observable, but I did not then expect that this rule would hold out for the remainder of the year. But after I had finished diagram No. 8, merely to see what kind of curve these months would present to the eye, I was struck with its appearance in shape, and induced to count the days from vertex to vertex, which, commencing with November 11, gave me the following numbers: 6, 5, 2, 5, 6, 4, 4, 3, 6, 4, 6, 3

5, 3, 4, 5, 3, 7, 3, 5, 4, 5, 3, 6, 6, 4, 4, 2, 4, 6, 5, 5, 3, 7, 4, 6, 4 = 167, of which the mean is 4.5 days, as the mean period occurring between every two successive heights or vertices.

The same process applied to the former diagram of the months of June to October, 1856, gives me the following numbers: 5, 4, 5, 3, 5, 3, 4, 4, 4, 5, 6, 5, 4, 6, 3, 4, 3, 4, 3, 6, 4, 3, 4, 6, 10, (= 2 + 5,) 5, 5, 5 128, of which the mean number is 4.4 days. For May, 1857, commencing with the 14th, the numbers are 3, 5, 5, 5, 3.

No matter whether the barometer had a perfect vacuum or not, the features of this remarkable phenomenon are the same. The two series of the above numbers, and the coincidence of their mean value, prove beyond a doubt that they are not the result of mere accident; but that this periodical fluctuation in the pressure of the atmosphere is subject to a certain law, of which I am ignorant.

Diagram No. 9 exhibits two curves of the mean temperature for Colonia Tovar for twelve months. The upper curve is the result of noting down the mean temperature for every third part of the month, and presents quite a different appearance compared with the lower curve, in which are noted down the mean temperatures of the whole months only. The latter part of April and the middle of September show the highest, and the middle of January the lowest temperature. July has usually a lower temperature than the three months on either side of it. The mean temperatures of the four meteorological seasons present the curious fact that three of them, spring, summer, and autumn, have exactly the same temperature, viz: 58.9, even to a fraction. The mean temperature of the year is 58.2; difference between the coldest and warmest month, 5.3.

The temperature of the primeval forest, about two hundred yards distant from my dwelling, was, on the 25th of April, at 1h. 30m. p. m., 61°, at the margin 64°, when at my house the thermometer was 65°. In a shady ravine I stuck the thermometer four inches deep into the spongy brown vegetable mould at different times of the day, and found the temperature always 59°, pretty near the mean temperature of the year. 58° or 59° may be considered to be the constant temperature of this region about twelve inches below the surface of the ground in shady places.

I have often observed that, whenever the sun breaks through the clouds and has been shining for a couple of hours, the thermometer fluctuates frequently very suddenly from one to four degrees, according as it is touched by a warmer or colder current of air proceeding from the differently heated localities of the soil; but when the sky is entirely overcast such changes never take place.

It seems somewhat remakable that, at Colonia Tovar, no heavy thunder-storms occur. Thunder and lightning are seldom strong enough to deserve to be mentioned. Trusting to past experience with regard to the absence of tempests, hurricanes, and whirlwinds, I have covered the roof of my house with very thin and light shingles, not nailed down, as is done in the States, but merely hung loosely upon laths without any weather-boarding at all. And yet, for two

years, they have remained in this position undisturbed by winds and weather.

The stars are here seen to scintillate on every clear evening the same as they do in higher latitudes, with the exception of a small area in the zenith of about 45 degrees, where they have their steady planetary light mentioned by Humboldt, and to be observed in lower regions. The zodiacal light I have never been able to see in the colony, although I have looked for it every clear evening.

Besides the already enumerated tables and diagrams, I have also inclosed four sheets of copies of sculptured rocks, or, as they are called in this country, "piedras pintadas," (painted stones.)

These rocks, which I have found in different regions, in low hot valleys as well as on high cold mountains, seem to be the work of one and the same race of men. The original figures are on a large scale. A few well-preserved spots, sheltered by a layer of sandy soil against the destructive influence of the atmosphere, show that the outlines of these figures are grooves, engraved or chiseled very smoothly and regularly to the depth of at least an inch in the hardest rock, and evinces a skill which would do credit to any of the civilized inhabitants now living in this country, even when aided by tools of steel There is no mere scratching about them; they have been sculptured. They show clearly that they were worked to last, and to outlive full many a change in the history of nations. The delineations are in all of them, whether from the sultry and insalubrious coast of Puerto Cabello, or from the cold mountain regions of the colony, of the same kind of workmanship, consisting of grooves about an inch wide and an inch deep.

Time has worked sadly at most of these stones, and on some of them I found only traces of figures.

All these rocks I found by accident in my botanical rambles, in places where I never would have ventured to penetrate, and where I was led by necessity when strayed and trying to find my way back.

Whatever may be said of these figures, patiently worked into the rock, they were not done without a certain design. Whether they were intended to convey any peculiar meaning, or none at all, the Indians have hereby bequeathed to us the means of comparing them with similar monuments in other distant regions. So much is certain, they were worked with the intention to remain there for a long period of time, and to be looked at by posterity. These figures consist in images of objects, with which their makers were surrounded and acqua nted, as, for instance, alligators or large lizards, snakes, tigers, canoes, sun, moon, human heads, &c., but show no signs of implements of civilization. Therefore these figures may be supposed to date anterior to the conquest of the country by the Spaniards. No record of the existence of these rocks, I suppose, has hitherto ever been made, for this region has been discovered but very lately, and none of the natives living in the neighboring valleys have known anything about them. In this case I may have been the first and only stranger who ever beheld their yet lasting works, of which they took so much pains to make a show in after years.