Letter from M. Humboldt to M. Delambre, relative to his Travels in South America.

my respectable friend, Lima, December 25, 1802.

I AM just arrived from the interior of the country, where, in an extensive plain, I made experiments on the small horary variations of the needle; and I learn with regret that the frigate Astigarraga, which was not to have gone this fortnight, has hastened her departure for Cadiz, and sails this very night.

It is the first opportunity for sending to Europe that has occurred these five months in the solitudes of the southern ocean; and the want of leisure prevents my writing as I could wish to the National Institute, which has just bestowed on me the most signal mark of the interest and favor with which it honors me.

It was a few days before my departure for Jaen and Amazonia that I received the letter dated 2 Pluviose, year 9, which that illustrious society adressed to me through you.

It was two years in reaching me among the Cordilleras of the Andes.

I received it the day after I had returned from a second expedition to the crater of the volcano Pichinca, to which I took an electrometer of Volta.

I measured its diameter, which I found to be 752 fathoms, while that of Vesuvius is but 312.

A considerable time before I received your letter, I addressed three letters successively to the physical and mathematical class, two from Santa Fe de Bogota , accompanied with a work on the genus Cinchona, or Quinquina, consisting of specimens of the bark of seven species, coloured drawings representing those productions, with the anatomy of the flower which differs so much in the length of its stamina, and the flowers themselves dried with care.

Dr. Mutis presented me with about 100 splendid drawings in large folio, representing the new genera and species of his manuscript Flora of Bogota . This collection, as interesting to the botanist as it is remarkable for the beauty of the colours, could not, in my opinion, be in better hands than those of Jussieu, Lamarck, and Desfontaines; I have therefore offered them to the National Institute as a feeble mark of my attachment.

This collection, together with the drawings of the Cinchona, set off for Carthagena in the month of June of the present year, and M.

Mutis himself has undertaken to procure their conveyance to Paris.

A third letter for the Institute left Quito with a geological collection of the productions of Pichinca, Cotopaxi , and Chimborasso.

The little leisure I have to day prevents me from giving you a sketch of my travels and accupations since our return from Rio Negro.

You know it was at Havannah that we received the false intelligence of Captain Baudin's departure for Buenos Ayres.

Faithful to the promise I had given to join him if I could, and persuaded that I should render greater service to the sciences by labouring in conjunction with the naturalists who accompany Captain Baudin, I did not hesitate a moment in sacrificing the insignificant honor of completing my own expedition, and instantly hired a small vessel at Bataban, for Carthagena.

Stormy weather prolonged this short passage above a month.

The trade-winds had ceased in the South Sea, where I imagined I should find Captain Baudin, and I undertook the difficult journey through Honda, Ilague, the passage of the mountain of Quindin, Popayan, Pastos, and Quito.

My health withstood, in a wonderful manner, the changes of climate to which we were exposed on this route; descending every day from snowy regions, at an elevation of 2,460 fathoms, into burning vallies, where Reaumur's thermometer never falls below 26° or 24°.

My companion, M. Bonpland, whose abilities, courage, and unwearied activity were of the greatest assistance to me in my botanical and anatomical researches, has been afflicted with tertian fevers for two months.

The rainy season overtook us in the most critical part of our journey, the elevated plain of Pastos; and after travelling eight months, we arrived at Quito, where we heard that Captain Baudin had taken the route from west to east by the Cape of Good Hope.

Accustomed to disappointments, we consoled ourselves with the idea of having made such great sacrifices with good intentions.

Looking at our collection of observations of different kinds, our drawings and experiments on the atmosphere of the Cordilleras, we did not regret having traversed countries which have in a great measure never been visited by any naturalist. We felt that man must not rely upon any thing but what he can produce by his own energy.

The province of Quito, the most elevated plain in the world, and convulsed by the great catastrophe of the 4th of Feb. 1797, afforded us a vast field for physical observations.

Volcanoes of such magnitude, that the flames frequently rise 1000 yards above their summits, have never yet produced a drop of melted lava: they vomit forth water, sulphureous hydrogen gas, mud, and carbonated clay.

Since 1797, all this portion of the globe has been in agitation; we every moment feel the most alarming shocks; and the subterraneous rumbling in the plains of Rio Bamba is like that of a mountain falling to ruins beneath our feet.

The atmospheric air and humid earth appear to be the grand agents of these combustions and subterraneous fermentations, all the volcanoes being formed of decomposed porphyry.

It has hitherto been imagined at Quito, that 2,470 fathoms were the greatest elevation at which man can resist the rarefaction of the air.

In March 1802, we passed several days in the great plains which surround the volcano of Antisana, at the height of 2,107 fathoms, where the oxen, when pursued, frequently vomit blood.

On the 16th of March, we discovered a road upon the snow, by which, with a gentle acclivity, we ascended to an elevation of 2773 fathoms.

The air there contained ,008 of carbonic acid, ,218 of oxygen, and ,774 of azote.

Reaumur's thermometer was only 1,5°. it was by no means cold, but the blood issued from our mouth and eyes.

The situation would not admit of our making experiments with Borda's compass, excepting in a cavern lower down, at 2467 fathoms: the intensity of the magnetic power was greater at this height than at Quito, in the proportion of 230 to 218; but it must not be forgotten, that frequently the number of oscillations increases when the inclination is diminished, and that the intensity is augmented by the mass of mountains, the porphyry in which affects the magnet.

In our expedition to Chimborasso, the 23d of June, 1802, we proved, that, with patience, it is possible to endure a still greater degree of rarefaction of the atmosphere.

We reached 500 fathoms higher than La Condamine (at Carazon); and at Chimborasso we carried instruments to the elevation of 6,062 yards, where we observed the mercury of the barometer descend to 13in.

11,2 lines; the thermometer was 1°,3 below zero.

We likewise bled here at the mouth.

Our Indians left us as usual. M.

Bonpland and M. Montufar, son of the Marquis of Selvalegre, of Quito, were the only persons who remained with me.

We felt a certain indisposition, debility, and inclination to vomit, which are certainly owing as much to the want of oxygen in those regions as to the rarefaction of the air. I found only ,20 of oxygen at this immense height.

A tremendous cleft prevented us from reaching the very summit of Chimborasso, of which we only wanted 472 yards.

You know that the height of this immense colossus is still uncertain; that La Condamine, who measured it at a great distance, makes it about 6,440 yards, while Don George Juan computes it to be 6,760; and that this difference does not arise from the different heights which these astronomers adopt for the signal of Carabura.

In the plain of Tapia I measured a base of 1,702 metres.

According to two geometrical operations, I calculate Chimborasso at 6,534 yards above the level of the sea.

The volcano of Tunguragua has greatly diminished since the time of La Condamine: instead of 2,620 fathoms, I find that it is now not more than 2,531; and I am convinced that this difference does not arise from an error in the operations, because in my measures of Cayamba, Antisana, Cotopaxi , Iliniza, I differ but 10 or 15 fathoms from the results of La Condamine and Bouguer.

All the inhabitants, likewise, of this unfortunate country say that Tunguragua is perceptibly diminished.

On the other hand, I find Cotopaxi, which has had such dreadful eruptions, of the same height as in 1744, or, if any thing, rather higher, which may perhaps proceed from some error of mine.

But the stony summit of Cotopaxi shews that it is a chimney capable of resistance and of preserving its figure.

The operations which we undertook, from January to July, in the Andes of Quito, gave the inhabitants the melancholy information that the crater of Pichinca, which La Condamine saw full of snow, burns afresh; and that Chimborasso, which has been thought so tranquil and innocent, has been a volcano, and will perhaps be so again.

We found burnt rocks and pumice-stone at the height of 6,062 yards.

Unfortunate will it be for mankind if the volcanic fire (for the whole elevated plain of Quito may be said to be a single volcano with several summits) breaks forth from Chimborasso.

It has frequently been asserted that this mountain is granit, but it contains not an atom of that substance.

It is composed of porphyry here and there in columns, inclosing vitreous feldspar and olivine.

This stratum of porphyry is 3,800 yards in depth.

Besides the elephants' teeth which we sent to M. Cuvier, from the plain of Santa Fe, at an elevation of 2,700 yards, we have preserved for him several finer; some of them belonging to the carnivorous elephant, and others somewhat different from those of Africa, from the valley of Timana, the town of Ibarra and Chili.

Thus it is ascertained that this carnivorous monster existed from the Ohio, or 50° of north latitude to 35° south.

I have spent a very agreeable time at Quito.

The president of the audience, Baron de Carondelet, has loaded us with favors; and during my peregrinations of three years, I have not had reason to complain one single day of the agents of the Spanish government which has treated me with a delicacy and distinction that entitle it to my everlasting gratitude.

How times and manners have changed!

After passing through Assonay and Cuenca, where we were entertained with bull-fights, we took the road to Oxa, to complete our labours on the Cinchona.

We then spent a month in the province of Jaen de Bracamorros and the Pongos of the Amazons, whose banks are embellished with the Andiva and Bougainvillaea of Jussieu. It appeared to me an interesting object to fix the longitude of Tomependa and Cluechungat, where La Condamine's map begins, and to connect those points with the coast.

La Condamine could ascertain only the longitude of the mouth of the Napa; time-keepers were not then in existence, so that the longitudes of these countries must require correcting.

My chronometer, by Louis Berthoud, is wonderfully correct, as I find by my own observations and by comparing point for point my differences of the meridian with those found by the expedition under M. Fidalgo, which, by the king's command, has been making trigonometrical operations from Cumana to Carthagena.

From the Amazons we crossed the Andes to the mines of Hualgayoe, which yield a million of piastres per annum, and where the silver ore is found at the depth of 2,065 fathoms.

We descended by Cascamusca, or the palace of Atahualpa, where I took drawings of the arches of the Peruvian vaults, to Truxillo, pursuing our route through the deserts along the coast of the South Sea to Lima, where, during half the year, the sky is obscured by thick vapours.

I hastened to reach Lima, to observe there the passage of Mercury on the 9th of Nov. 1802.

Our collections of plants, and the drawings which I have made of the anatomy of the genera, conformably to the ideas communicated to me by M. Jussieu, have been considerably augmented by the riches we discovered in the province of Quito, at Loxa, near the Amazons, and in the Cordilleras of Peru.

We have found many of the plants described by Joseph de Jussieu as the Lloque affinis, Quillajae, &c. We have a new species of Jussiaea, which is charming, of colletia, several passion-flowers, and the coranthus in the form of a tree 60 feet in height.

We are, in particular, very rich in palm-trees and grasses, on which M. Bonpland has drawn up a very extensive work.

We have now 3,784 very complete descriptions in Latin, and nearly onethird of that number of plants in our herbaries, which we have not had time to describe.

There is not a vegetable but what we can point out the rock it inhabits, and the number of fathoms it is in height; so that the geography of plants will find in our manuscripts very accurate materials.

To render them more perfect, M.

Bompland and myself have frequently written separate descriptions of the same plant: but two-thirds, and more, of the descriptions are the fruit of M. Bonpland's assiduity alone; his zeal and exertions for the promotion of the sciences cannot be too much admired.

We compared our herbaries with those of M. Mutis, and consulted a vast number of books in the immense library of that great man.

We are persuaded that we have many new genera and new species; but it requires much time and great labour to decide what is really new.

We likewise have a silicious substance resembling the tabascher of the East Indies, which M. Mace has analysed.

It exists in the joints of a gigantic species of grass, which is confounded with the bamboo, but the flower of which differs from the bambusa of Schreiber. I know not whether M. Fourcroy ever received the milk of the vegetable cow (a tree so called by the Indians), which, when treated with nitric acid, yielded a caoutchouc with an aromatic smell, but which, far from being caustic and injurious like all vegetable milks, is nourishing and agreeable to drink.

We discovered it on the road to the Oronoko, in a plantation where the negroes drink it in great quantity.

I likewise sent to M. Fourcroy, by way of Guadaloupe, and to Sir Joseph Banks, by way of Trinidad, our Dapiche, or oxygenated white caoutchouc, which oozes from the roots of a tree in the forests of Pimichin, in the remotest corner of the earth near the sources of Rio Negro.

I shall not go to the Philippines, but shall proceed by way of Acapulco, Mexico, and the Havannah, to Europe, and hope to embrace you in September or October, 1803, at Paris.

Health and respect, (Signed)

HUMBOLDT.

In February I shall be at Mexico; in June, at the Havannah. I think of nothing but the preservation and publication of the manuscripts I possess.