Letter from M. A. Humboldt to C. Delambre, Member of the French National Institute.

New Barcelona, Nov. 24, 1800.

DURING my stay in South America I dispatched several letters to you and Lalande; I know you are interested in my fate, and I never let slip an opportunity of writing to you, though I have scarcely any hopes of my letters reaching the place of their destination.

I am now on the point of setting out for the Havannah and Mexico, after having performed a tour of thirteen hundred nautical leagues in this part of the New World, situated between Popayan, Quito, and Cayenne. I have slept for three months in the open air, in the woods, surrounded by tigers and hideous serpents, or on plains covered with crocodiles.

Bananas, rice, and manioc, have been our sole nourishment; for all provisions soon become putrid in this damp and scorching country.

How grand and majestic is nature among these mountains!

From Baraquan and Uruana, which unknown nations have covered with hieroglyphics, as far as the volcano of Duida, at the distance of sixty leagues from the small lake of Dorado, the elevation of which I have found to be 2176 metres, there is only one cordillera of granite, that descends from Quito, and proceeds from west to east to join the mountains of the French part of Guyana.

What variety among the Indian races!

All free, all governing themselves and eating each other, from the Guaicas of Gehetta, a pigmy nation, the largest of whom are about four feet two inches in height, to the white Guajaribos, who have really the whiteness of Europeans; from the Otomacos, who eat a pound and a half of earth per day, to the Marivitanos and the Magueritares, who feed on ants and resin.

Having already spoken of all these in a letter, which I dispatched from the mouths of the Orenoquo to our good friend Pommard, I shall confine myself at present to a few astronomical observations, which, I think, I have made with a considerable degree of care.

This letter, when this was published, had not reached France

My time-keeper, by Berthoud, continues to go with great correctness.

I regulate it every four, five, or six days, by corresponding altitudes, taken with my instruments, which do not err a second; viz.

sextants by Ramsden and Troughton, a quadrant by Bird, and a horizon by Carroche.

You know that I am not very learned in the mathematics, and that astronomy is not the object of my travels; yet with zeal and application, and by daily handling the same instruments, I have been able to do something, and to do it better.

As I traversed a country never visited by Europeans till about thirty years ago, in which all the Christian missions do not amount to 1800 souls, and consequently where no one has ever yet been able to make observations, I conceived that I ought not to neglect so favourable an opportunity of enlarging our geographical knowledge.

You would have laughed had you seen me amidst the Ydapamianeres Indians in the forest of Casquiara, with my instruments mounted on boxes or trunks, while the shells of tortoises served us as stools.

Eight or nine apes, which we carried with us, had a strong desire to handle my hygrometers, barometers, and electrometers also: around all these ten or twelve Indians stretched out in their hammocks, together with fires to secure us from the tigers, which are no less ferocious here than in Africa.

The want of nourishment, the mosquitoes, the ants; the chigers, which enter the skin and plough up the flesh; the desire of cooling ourselves in the water, and the impossibility of doing it on account of the ferocity of the caymans, the danger of being pricked by the rajas and the teeth of the small caribfish--youth and a great deal of resignation are required to endure all these.

The evil is passed, and I have reaped more than I durst venture to hope.

It is believed (see the map of father Caulin, the best extant, though all the names are wrong,) that the Spanish possessions of Guyana extend to the equator.

But I have found, by very good observations of the stars called the Cross and Canopus, which I made among the rocks of Culimacari, that San Carlos del Rio Negro, the most southern establishment, is in 1° 53' of north latitude; and that the line passes through the government of Great Para, near St. Gabriel-delas-Cachuellas, where there is a cataract, but not so considerable as the two famous ones of Atures and Maypura.

At Cumana, before the earthquake, which we experienced on the 4th of November 1799, the magnetic inclination, measured with Borda's compass, was found to be 44° 20' of the new division: after the earthquake it was 43° 35'; the needle made 229 oscillations in the course of ten minutes.

Experiments have proved that the magnetic charge has changed in this part of the world, and not in the needle.

At Calabozo, in the centre of Uana, lat. 8° 56' 56", long. from Paris 44° 40' 18", the inclination was 39° 30': number of oscillations 222.

At Atures, one of the cataracts of the Orenoquo, in lat. 5° 39', long. 44° 42' 19", the inclination was 32° 85': number of oscillations 221.

At St. Fernando d'Atabapo, a mission at the mouth of the Guaviara, lat. 4° 9' 50", the inclination was 30° 30': number of oscillations 219.

At St.

Carlos de Rio Negro, lat. 1° 53', the inclination was 23° 20: number of oscillations 216.

According to the rules given by Messrs. Cavendish and Dalrymple, care was always taken, while observing, to turn the compass to the east and west to find the mean inclinations, and to correct the error which takes place when the axis of the needle does not pass exactly through its two points.

During this journey, which lasted a year, I determined 54 points of South America, in which I observed the latitudes and longitudes: the former deduced, for the most part, from the meridian altitude of two stars at least; and the latter, either from the distances of the moon from the sun and stars, or from the time-keeper and horary angles.

I am now employed in constructing a map of the country through which I have travelled; and as my observations fill up the vacuum found in the maps between Quito and Cayenne, to the north of the river of the Amazons, I flatter myself that they will be interesting to geographers.

My time-keepers have not given me with exactness, but the differences of meridian between the places of my departure and the Caraccas, Cumana, and St. Thomas de Nueva-Guayanna, lat. 8° 8' 24", long. 21 of time, east from Cumana. I am very anxious, therefore, on account of my map, to fix the position of these three places in regard to Paris, and by observations purely astronomical.

Besides, it is very necessary that navigators should be able, at the time of their arrival on this coast, to find the longitude of the ports well determined, that they may know the state of their chronometers; for, except Martinico, Guadaloupe, Portorico, where M. De Churucca observed; Cayenne, and Quito, there are very few places the longitude of which can be depended on; especially in Spanish America.

Carthagena, according to the Connoissance des Temps, is at 5 h. 12' 12".

But the three emersions of the satellites, observed by Herrera, all give 69° 24' 10" west of Cadiz, or 5 h. 13' 11" to the west of Paris.

I observed, with a telescope of Dollond, which magnifies 95 times, at Cumana, in lat. 10° 27' 37":

The immersion of the second satellite Nov. 7, 1799, at 11 h. 41' 18' true time.

Of the second satellite, Sept. 11, at 16 h. 31' 0" true time.

Of the first satellite, Sept. 25, 1800, at 17 h. 10' 21" mean time.

The emersion of the 4th satellite, Sept. 26, at 17 h. 28' 0" mean time.

Of the third satellite, Sept. 27, at 16 h. 25' 55" mean time.

Of the fourth satellite, Sept. 26, at 17 h. 28' 0" mean time.

I am therefore mistrustful of the longitude of Cumana, as given me by my time-keeper.

When I arrived from the Canaries at the Continent, I found the longitude to be 4 h. 26' 4"; and the observations of M. Fidalgo, who observed emersions at Trinidad, but not at Cumana, give still more; viz.

4 h. 26' 16".

Fidalgo found Trinidad 55° 16' 32" to the west of Cadiz, and Cumana 2° 41' 25" to the west of Puerta Espanna.

But the map of Trinidad, published at London, from the excellent observations of M. De Charucca, makes Puerta Espanna 61° 22' west from London. I am of opinion, therefore, that, in constructing the map, the authors had before them the calculations by Lalande of the occultation of Aldebaran, observed at Porto Rico on the 21st of October 1793; for the capital of Porto Rico is by the time-keepers 4° 34 to the west of Puerta Espanna, calculating the longitude by that of Porto Rico 63° 48 15"; and for Cumana 66° 29' 40" to the west of Paris.

The five eclipses of the satellites which I send you, must throw light on this subject; and, in my opinion, the longitude of Cumana will not be much beyond 4 h. 25' 20".

Unfortunately, the eclipse of the sun, which I completely observed on the 28th of September at Cumana, making the horns pass along the horizontal and vertical wires, was not visible in Europe. I observed the end at 8 h. 14' 22" mean time; the time certain to 1" nearly, having taken corresponding heights the same day.

At Carras (Plaza della S. Trinidad) lat. 10° 31' 4", I observed:

The immersion of the first satellite, Dec. 7, 1799, at 16 h. 11' 57" true time.

Of the third satellite, Dec. 7, at 17 h. 11' 36" true time.

The emersion of the first satellite, Jan. 17, 1800, at 11 h. 14' 8" mean time.

Of the second satellite, Jan. 28, at 7 h. 58' 8" mean time.

Of the fourth satellite, Jan. 18, at 8 h. 13' 3' mean time.

At the Valle del Tuy al Pic della Cocuiza, lat. 10° 17' 23".

The emersion of the first satellite, Feb. 9, 1800, at 11 h. 26' 57" mean time.

Of the third satellite on the 10th of February, at 7 h. 58' 50" mean time.

But these last eclipses were observed with a telescope of Caroche, which, though a very good one, magnifies only 58 times, not being able to carry along with me, to Rio-Negro, the large telescope by Dollond.

Declination of the magnetic needle at Cumana on the 27th of October 4° 13' 45"; at Caraccas, 4° 38' 45"; at Calabozo, 4° 54' of the old division.

The port of La Guayra is exactly 29" in time west from Caraccas; and I hope that, by giving immersions and emersions, the meridian of Caraccas will be properly fixed.

I have described, with Bonpland, more than 1200 plants.

A letter from Haspel-la-Chenaye, chemist at Guadaloupe, dated Jan. 5, states, that M. Humboldt had set out for the Havannah, after having left with the agent of the government at Guadaloupe a box for the Institute and two packets, one for Fourcroy and the other for Delambre.

As the box has not yet arrived, nor the packets addressed to Fourcroy, it is to be presumed that the above letter is not that mentioned by Haspella-Chenaye