copy of a letter read in the class of physical and mathematical sciences.

Alexander Humboldt to Citizen Delambre, Perpetual Secretary of the National Institute.

From Lima, the 25th November, 1802. my worthy friend,

I JUST arrive from the interior of the country, where I have made experiments on a wide plain on the hourly variations of the magnetic needle, and learn with regret that the frigate Astigaragga which was only to have departed in a fortnight, is now going to set sail for Cadiz this very night.

For these five months it is the first opportunity we have had for Europe in the solitary regions on the Pacific Ocean; and want of time renders it impossible for me to write as I ought to the National Institute, from which I have just received the most affecting proofs of the kindness with which it honours me. A few days before my departure from Quito for Jaen and the Amazone, I received the letter which that Society addressed to me by your hands.

It is dated the 2d Pluviose, 9th year, and has taken two years to reach me in the Cordillieras of the Andes.

It came to hand the day after my second expedition to the crater of the volcano of Pichincha, whither I had gone with an electrometer of Volta, and to measure the diameter, which I find to be 752 toises, while that of Vesuvius is only 312. This reminds me that on the summit of Guaguapichincha, (where I have been often, and which I regard as classical ground,)

La Condamine and Bouguer received their first letter from the ci-devant Academy; and I imagine that Pichincha, si magna licet componere parvis, is a lucky spot for natural philosophers.

How shall I express to you, Citizen, the satisfaction with which I perused this Letter of the National Institute, and the repeated assurance of your kind remembrance.

How delightful is it to know that we live in the memory of those whose labours daily advance the progress of the human mind!-- In the deserts of the plains of Apure, in the thick forests of Casiguian and of the Orenoque, every where your names have been present to me; and running over in thought the different epochs of my wandering life, I have dwelt with transport on those of the 6th and 7th year, when I lived in the midst of you, and where Laplace, Fourcroy, Vauquelin, Guyton, Chaptal, Jussieu, Desfontaines, Halle, Lalande, Prony, and especially you, my generous and affectionate friend, loaded me with kindness in the plains of Lieursaint.

Accept all of you together the homage of my tender attachment and my constant gratitude.

Long before I received your letter in your capacity of Secretary to the Institution, I addressed successively to the Physical and Mathematical Class, three letters; two from Santa-Fe de Bogota, accompanied with a treatise on the genus Chincona, (that is to say, specimens of bark of seven species; coloured drawings representing these vegetables with the anatomy of the flowers so different as to the length of the stamina, and skeletons dried with care.)

Doctor Mutis, who behaved most kindly to me, and for whose sake I went up the river La Madelaine forty days journey, has made me a present of more than one hundred magnificent draughts, large folio, giving figures of new genera, and new species of his manuscript Flora of Bogota. I thought that this collection, as interesting for botany as remarkable for the beauty of the colouring, could not be in better hands than in those of Jussieu, Lamarck, and Desfontaines; and I have offered it to the National Institute as a feeble mark of my attachment.

This collection and the Chinconas were sent for Carthagena in South America about the month of June this year: M.

Mutis himself took in hand to forward them to Paris.

A third letter for the National Institute was sent from Quito, with a geological collection of the productions of Pichincha, Cotopaxi, and Chimborazo.-- How afflicting is it to remain in a sad uncertainty concerning the arrival of these articles, and of the collections of rare grains which three years ago we directed to the Jardin des Plantes at Paris!

My time is too short to-day to give you an account of my travels and occupations since my return from Rio-Negro.

You know that it was at the Havannah we received a false report of the departure of Captain Baudin for Buenos-Ayres.-- Faithful to my promise of joining him wherever I could, and persuaded I should be more useful to science by uniting my labour to that of the naturalists who follow Captain Baudin, I did not hesitate a moment to sacrifice the little glory of finishing my own expedition; and I freighted immediately a small vessel at Batabano, in order to proceed to Carthagena.

Storms retarded this short passage upwards of a month, as the gales had ceased in the Southern Ocean, where I expected to fall in with Captain Baudin. I entered on the difficult route of Honda, of Ibague, of the passage of the mountain of Quindiu, of Popayan, from Pasta to Quito.

My health continued to resist wonderfully well the change of temperature to which one is continually exposed in this route, descending every day from snows of 2460 toises, to scorching valleys, where Reaumur's thermometer is never below twenty-four or twenty-six degrees.

My companion, whose knowledge, courage, and immense activity have been of the greatest use to me in researches on botany and comparative anatomy, Citizen Bonpland, has been ill of the tertianague for the space of two months.

The rainy-season overtook us in the most critical passage, on the flats of the Pastas, and after a journey of eight months we arrived at Quito, where we learned that Citizen Baudin had taken his route from West to East by the Cape of Good Hope.

Accustomed to disappointments, we comforted ourselves with the thoughts of having made so great sacrifices with a good design.

On looking at our herbarium, our measurements, barometrical and geodesical, our drawings, our experiments on the air of the Cordillieras, we did not regret having visited countries, the greater part unknown to naturalists.

We felt that man can depend on nothing but what is produced by his own energy.

The province of Quito, the most elevated flat in the world, rent by the great catastrophe of the 4th February 1797, has opened to us a vast field for natural observations.

Such enormous volcanoes, whose flames rise often to the height of one thousand metres, have never produced any lava.

They emit water, hydrogen, sulphurated gaz, mud, and carbonated argile.

Since the year 1797 the whole of this part of the globe is agitated.

We feel every moment dreadful shocks; and in the plains of Riobomba the subterraneous noise resembles that of a mountain falling to pieces beneath our feet.

The atmospheric air and the humid lands (all these volcanoes are in a decomposed porphyry,) appear the great agents of these combustions, of these subterraneous fermentations.

Hitherto it was believed at Quito, that 2470 toises was the greatest height where men could resist the rarefaction of the air.

In the month of March 1802, we spent some days in the vast plains which surround the volcano of Antisana at 2107 toises, where the cattle, when pursued, often vomit blood.

The 16th of March we discerned a path on the snow, a gentle slope, on which we mounted to the height of 2773 toises.

The air contained 0,008 of carbonic-acid, 0,218 of oxigen, and 0,774 of azote.

The thermometer of Reaumur was only at 15°; it was not in the least cold, yet we bled at lips and eyes.

The site did not permit us to make an experiment with the compass of Borda, but in a grotto at 2467 toises.

The intensity of in magnetic power was greater at that height than at Quito, in the ratio of 230 to 218. But it is not to be forgot, that often the number of oscillations increases when the inclination diminishes, and that this intensity is increased by the mass of the mountain whose porphyries affect the magnetic needle.

In the expedition I made on the 23d of June 1802, to the Chimborazo, we have experienced that with patience one may support a still greater rarefaction of air.-- We reached to a greater height than La Condamine (on the Corazon,) by 500 toises.

We carried instruments on the Chimborazo to 3031 toises; seeing the mercury descend in the barometer to 13 inches 11, 2 lines; the thermometer being 1° 3' below zero.

We bled still at our lips.

Our Indians forsook us as usual.-- Citizen Bonpland and M. Montufar, son of the Marquis of Selvalegre at Quito, were the only people who persisted: we all felt an uneasineß, a debility, an inclination to vomit, which certainly proceeds from the defect of oxygen in these regions more than from the rarified air. I found only 0.20 of oxygen at this immense height.-- A horrid fissure prevented us from reaching to the very summit of Chimborazo, from which we were only 206 toises.

You know that the height of this colossal mass is still uncertain.

La Condamine measured it from a great distance.

He allows it nearly 3220 toises.

Don George Juan gives it 3380.

This difference does not proceed from the various altitudes which these astronomers adopt for the signal of Carabouron. I measured in the plain of Tassia a base of 1702 metres, (forgive me for speaking sometimes of toises and sometimes of metres, according to the difference of the instruments I use:

you may be sure that in publishing my operations I shall reduce the whole to the metre and to the centigrade thermometer).

Two geodesical operations give me Chimborazo 3267 toises above the sea: but the calculation must be rectified by the distance of the sectant from the artificial horizon, and other circumstances.

The volcano Tongouragoa has diminished much since the time of La Condamine; instead of 2620 toises, I find it only 2531; and I hope this difference does not proceed from an error in my operations; since in my measures of Cayambo, Antisana, Cotopaxi, and Illinga, I do not differ more than 10 or 15 toises from the result of La Condamine and Bouguer.-- All the inhabitants of these miserable countries say that Tongouragoa is perceptibly lower, while Cotopaxi, which has had so violent explosions, is as high as in 1744, and even somewhat higher, unless that arise from an error on my side.

But the rocky summit of Cotopaxi shews that it is a chimney which resists and preserves its figure.

The operations we have made in the Andes of Quito, from January to July, brought the inhabitants the sad news that the crater of Pichincha, which La Condamine saw full of snow, burns anew; and that Chimborazo, whom they thought so peaceable and harmless, has been a volcano, and perhaps one day will be so again.

We have burnt rock and pumicestone at the height of 3031 toises.

Woe to mankind if the volcanic-fire (for we may say that the flat of Quito has been one volcano with several tops,) breaks forth through the Chimborazo.

It has often been said in print that this mountain is of granite; but there is not one atom of that.

It is here and there porphyry in columns, encrustating vitrous field-spath, horn-stone, and olivin. The bed of porphyry is 1900 toises thick.

I might mention to you on this occasion a polar porphyry, which, analogous to the serpentine I have described in the Journal de Physique, has poles without attraction: I might quote to you other facts relating to the great law of the stratas, and their enormous thickness near the equator: but it would be too much in a letter which may be lost; and I will treat of that some other time.-- I only add, that besides the elephants'- teeth which we have sent to Citizen Cuvier from the flats of Santa Fe, of 1350 toises in height, we keep for him others still finer; some of a carnivorous-elephant, others of a species little different from that of Africa, from the valley of Timana, the town of Ibarra, and from Chili.

Thus, then, is the existence of that carnivorous monster certain from Ohio, in the 50th° north latitude to the 75th° south latitude.

I have spent very agreeable hours at Quito.

The President of the Audience, Baron de Corondeles, has loaded us with kindness; and for three years I have had no reason to complain for once of the Agents of the Spanish Government.-- Every where I have been treated with distinction, and with a delicacy which obliges me to an everlasting gratitude.

I have been very attentive to the pyramids and to their foundation, which I do not believe in the least deranged as to the Pierres Molaires.

A generous individual, a friend of sciences and of learned men, such as La Condamine, Godin, and Bouguer--namely, the Marquis of Selvalegre, at Quito, thinks of rebuilding them--but this leads me too far.

After having passed the Assonay and Cuenca, (where they gave a bull-baiting,) we took the route of Loxa, to complete our operations on the Chincona.

Afterwards we spent a month in the province of Jaen , of Bracomoros, and in the Pongos of the Amazone, whose banks are adorned with the Andira and Bougainvillea of Jussieu.

Methinks it is important to fix the longitude of Tomependa and of Chuchanga, where begins the chart of La Condamine, and to connect these points with the coast.

La Condamine could only fix the longitude of the mouth of the river Napo: there were then no time-pieces; so that the longitude of these places stand in need of several corrections.

My chronometer of Louis Berthoud does wonders, as I am convinced by observing from time to time the first Satellite of Jupiter; and by comparing point for point the difference of my meridians from those found at the expedition of M. Fidalga, who, by the King's order, made trigonometrical observations from Cumana to Carthagena.

From the river Amazon we passed the Andes by the mines of Haalgayac, which produce a million of piastres yearly, and where the mine of grey argentiferous copper is found at 2065 toises.

We came down to Truxilla by Cascamarca, (where, in the palace of Atatualpa, I have drawn the arches of the Peruvian vaults.

Continuing by the deserts of the South Sea Coast to Lima, where one half of the year is covered with thick vapours, I made haste to arrive at Lima, in order to observe the Transit of Mercury on the 9th Nov. 1802.

Our collections of plants, and the drawings I have made of the anatomy of the genera, agreeably to the ideas Citizen Jussieu had imparted to me in the Society for Natural History, have greatly increased the riches we have found in the province of Quito, at Loxa, at the Amazone, and in the Cordillieres of Peru.

We have found many plants seen by Joseph Jussieu, such as the Llogue affinis quillajac, and others.

We have a new species of julienne, which is charming; collatix, passiflora, and loranthus, a tree sixty feet high.

We are very rich in palms and gramina, on which Citizen Bonpland has laboured very extensively.

We now have 3784 very complete descriptions in Latin, and nearly one third of the plants in the Herbarium, which, for want of time, we have not been able to describe.

There is not a vegetable of which we cannot point out the rock it inhabits, and to what height in toises it mounts; so that the geography of plants will find in our manuscripts very correct materials.

In order to do still better, Citizen Bonpland and I have often described the same plant separately.

But two thirds of the descriptions, and more, belong to the sole assiduity of Citizen Bonpland, whose zeal for the progress of science cannot be sufficiently admired.

Jussieu, Desfontaines, and Lamarck, have reared in him a disciple who will go great lengths.

We have compared our herbarium with those of M. Mutis; we have consulted many books in the immense library of that great man: we are persuaded that we have found several new genera and new species: but much time will be required to determine what is really new.-- We mention also a silicious substance analogous to the tabaschin of the East Indies, which M. Mutis has analysed.

It is found in the knots of a gigantic gramen which is confounded with the bambou; but its flower differs from that of the bambusa of Schreber. I know not whether Citizen Fourcroy has received the milk of the vegetable-cow, (as the Indians call the tree.)

It is a milk which, prepared with nitrous acid, produced a caoutchouc with a balsamic odour, but which, far from being caustic and hurtful, as all vegetable milks are, is nourishing and agreeable: we discovered it on the the road of Orenoque, in a plantation where the negroes drink often of it. I sent also to Citizen Fourcroy by Guadaloupe, and to Sir Joseph Banks, by the Trinidad, our dapiche; or the white oxygen caoutchouc, which exudes from the roots of a tree in the forests of Pimichin, in the most remote corner of the world, towards the sources of Rio Negro.

At length, after waiting three years, La Mecanique Celeste of Laplace is arrived, (November 1802;)

I have fallen upon it with unbounded eagernefs.

This book has encouraged me to continue my researches on the tides of the atmosphere, on which I made several observations at Cumana in the year 1799. I have mentioned them in a letter to Citizen Lalande.-- Godin knew something about them, without pointing out a cause.

Mosely, in a work on the maladies of the Tropics, says, that the barometer is at the maximum when the sun is in the meridian; but that is very false.

The maximum takes place at 21 h. and at 11 h.; the minimum at 4 h. and at 15 [Formel] h. The Moon does not seem to alter the epochs so much as the quantity of elevations.

I am now observing principally the days of opposition and conjunction; and as my barometer indicates the 20th part of a line, I doubt not but Citizen Laplace, whose genius has conquered the tides of the sea, will also discover the laws of the tides of the air, when I shall have given him some thousands of observations.

See how striking the phenomenon is:

f. l.

24 November, 10 h. morn. 27 5 75 ------ ------ 12 49 m. 5 45 ------ ------ 2 0 5 25 ------ ------ 3 30 5 10 -------- ---- 4 45 5 0 -------- ---- 5 30 5 10 ------ ------ 7 0 5 40 ------ ------ 8 0 5 60 ------ ------ 9 0 5 65 ------ ------ 10 30 5 65

I observe the hygrometer and barometer at the same time.

My barometer is English.

I have gone too far.

I wished to write my friend Pommard. I have no more time; he loves me, he will excuse me.

I don't go to the Philippines. I pass by Acapulco, Mexico, Havannah, to Europe. I hope to embrace you in September or October 1803, at Paris.

I shall be at Mexico in February; in June at Havannah. I think of nothing but of preserving and publishing my manuscripts.-- How much do I long to be at Paris!

Health and respect, Humboldt.