Digitale Ausgabe

“Guyara, January 25, 1800. “As the yellow fever, which deſolates this part of SouthAmerica, obliges us to make our ſtay here as ſhort as poſ-ſible, I ſnatch this opportunity of ſending you a few lines,and repeating, from the middle of the torrid zone, how muchmy thoughts are occupied with you and your illuſtrious col-leagues, among whom I met with ſuch a flattering receptionduring my laſt ſtay at Paris. Since our departure from SaintCroix in Teneriffe, where I deſcended into the crater of thevolcano, the atmoſpheric air being there at 0·8 of R. andat 0·19 of oxygen, I have written to you twice. I have ſentto Delambre and Lalande an extract of my aſtronomicallabours; the longitude of ſome important places; an obſer-vation of the eclipſe on the 28th of October laſt; immerſions |276| of the ſatellites, and reſearches reſpecting the intenſity oflight of the auſtral ſtars, meaſured by means of diaphragms.I have addreſſed to the Inſtitute a chemical memoir on thephoſphoreſcence of the ſea; obſervations on a particular gasfurniſhed by the fruit of the coffea arabica when expoſed tothe ſun; on a ſnow white feld-ſpar, which, when moiſtened,abſorbs all the moiſture of the atmoſphere; experiments onthe milk of the cecropia peltata and the euphorbia curaſſa-vica, which will form a ſupplement to your excellent memoiron the cahout-chouc, and to that of our friend Chaptal; andon the air which circulates in vegetables. “The cruiſers which cover the ſeas here make me ap-prehend that a part of my letters may not have reached you;though I ſent them ſometimes by way of Guadaloupe, andſometimes by that of Spain. Theſe few lines I have ſent byan American veſſel, which will fail in a few days for Boſton;and, though they cannot reach you but through Hamburgh,they will, perhaps, be leſs liable to miſcarry. People hereare accuſtomed to make four or five duplicates of their letters.But how can I find time, when I have ſo many things toobſerve, arrange, and calculate? “I ſhall confine myſelf, therefore, to letting you oncemore know that I ſtill enjoy the beſt health poſſible, andthat I am treated with the utmoſt kindneſs by the inhabit-ants of theſe countries: that the paſſports and letters of re-commendation from the Spaniſh government procure meevery facility for making reſearches uſeful to the ſciences:that none of my inſtruments, even the moſt delicate, ſuch asbarometers, thermometers, hygrometers, Bordas’ dippingneedle, &c. are deranged: and that, at the extremity of themiſſionary eſtabliſhments among the Chayma Indians, inthe mountains of Toumiriquiri, I have my laboratorymounted as if I were in the Hotel Boſton, in the Rue duColombier. My fellow-traveller, Bonpland, educated in the Jardin des Plantes, becomes every day more valuable to me.To an extenſive knowledge of botany and comparative ana-tomy he unites indefatigable zeal. I hope one day to re-ſtore him to his country, worthy of attracting public atten-tion. Never did any foreigner enjoy ſuch permiſſion as that |277| granted to me by the king of Spain. This idea alone is ca-pable of exciting us to redouble our activity. During theſeven months we have been in this beautiful continent, wehave dried (with duplicates) nearly 4000 plants, writtenmore than 800 deſcriptions of new ſpecies or ſpecies littleknown, particularly new genera of palms, cryptogamia, bifaria,melaſtoma; collected inſects and ſhells, and made manydrawings reſpecting the anatomy of marine worms; withobſervations on magnetiſm, electricity, humidity, the tempe-rature of the atmoſphere, and the quantity of oxygen it con-tains. We have meaſured that immenſe and high chain ofmountains extending to the coaſt of Paria, and examinedtheir volcanoes, which vomit forth kindled inflammableair, ſulphur, and hydro-ſulphurous water. We have alſocollected many ſeeds, which we ſhall ſend off in three orfour weeks for Europe, addreſſed to the Jardin des Plantes. We have ſpent five months in the interior of New Anda-luſia and on the coaſts of Paria, where we experienced veryviolent earthquakes in the end of laſt year. One part of theſecountries is ſtill inhabited by the ſavage Indians, and othershave began to be cultivated only within ſive or ſix years. Inwhat words ſhall I deſcribe to you the majeſty of the vege-tation here; the foreſts of Ceiba, Hura, Hymenea, whichthe rays of the ſun never penetrate; the variety of the ani-mals; the ſuperb plumage of the birds; the apes, the tigers;the hideous aſpect of the crocodiles (caimans) which ſwarmin the rivers, and of which ſome are thirty feet in length?From Cumana we proceeded to Caraccas, where we remain-ed during the month of November and part of December:A charming capital ſituated in a valley which has 426 toiſesof elevation; and, though in latitude 10° 31′, enjoys thecoolneſs, and I might ſay the cold, of Paris! From thisplace we aſcended to the ſummit of the famous Silla de Ca-raccas, or Sierra de Avila, where, at the height of 1316toiſes, we diſcovered beautiful cryſtals of titanium. I foundalſo dendrites ſimilar to thoſe of manganeſe, which are oxydof titanium. We ſhall proceed hence for Varina and the ſnow-coveredmountains of Merida, the cataracts of Rio Nigro, and the |278| unknown world of Oronoco, in order to return by Guyanato Cumana, from which we ſhall ſet out for the Havannahand Mexico. “We ſhall take care to tranſmit the ſeeds we have col-lected for the Jardin des Plantes at Paris, the Muſeum, andSir Joſeph Banks, as we agreed with Juſſieu ‒ ‒ ‒ ‒. “How much I lament the fate of Dolomieu, detained apriſoner in Sicily! If he ſhould return, communicate to himthe following fact: — It is more than three years ſince I an-nounced to Lametherie, that, in the primitive mountains ofItaly, France, Swiſſerland, Poland, and I can now add Spain,there exiſts a paralleliſm of direction between the ſtrata offoliaceous granites, ſlate, micaceous ſchiſts, corneous ſchiſts:that theſe ſtrata incline (ſink down) towards the north-weſt,and that their direction makes with the axis of the globe anangle of 45° 57′: that this inclination and direction in nomanner depend on the form and direction of the mountains:that it is not any way affected by the valleys, but that itannounces a cauſe much greater, and more general: that itdepends on a phenomenon of attraction which has acted atthe time of the conſolidation of the globe. Having travelledover the greater part of Europe on foot, and with ſextantsand compaſſes, I have a very extenſive collection of obſerva-tions on that ſubject. My manuſcript on the identity ofſtrata in the conſtruction of the globe, is in the hands of mybrother. I was employed on it ſince 1791, but it will notappear till I have ſeen more of the globe. To my great aſto-niſhment, I have obſerved in the Cordillera of Paria, NewAndaluſia, New Barcelona, and Venzuela, that in the newworld, near the equator, the ſtrata follow the ſame laws andthe ſame paralleliſm. “You remember the laſt ingenious obſervations of Cou-lomb on the air which iſſues with exploſion from the trunksof trees when they are pierced. I have made experimentson the cluſea roſea, in which (in the interior of the pneumato-chimiſer, veſſels of Hedwig, the vaſa cochleata of Malpighi,)there circulates an immenſe quantity of air. This air con-tains as far as \( \frac{35}{100} \) of oxygen. The leaves of the ſame tree,when expoſed to the ſun under water, do not give a cubic |279| mellimetre of air. This air, which circulates, certainlyſerves, as in the animal body, to coagulate the fihrous partby abſorption of oxygen. The cluſea is a milky plant, andelaſtic gluten is formed in it. “Though the purity of the atmoſpheric air amounts here,particularly in the night, to 0·305 of oxygen, I have foundthat the air contained in the pods and capſules of equinoctialplants, for inſtance the paullinia, is more azotous than ouratmoſpherie air. It does not exceed 0·24 or 0·25 of oxygen.The air in the culmi geniculati here, has only 0·15 of oxygen.All this proves that the air which circulates is purer, andthat the air which is in a ſtate of reſt, depoſited in the cap-ſules or utriculi, is leſs pure than atmoſpheric air. Theformer is recently produced by the organs which decompoſethe water: it proceeds to thoſe parts where it ought to ſerve,by its abundance of oxygen, to precipitate the fibrous prin-ciple to form the fibrous tiſſue. The other is the reſiduumof a gas which has already diſcharged theſe functions.

ALEX. HUMBOLDT.”