paris academy of arts and sciences.

Meeting held on the 17th instant.

Letter from Bonpland:

his Botanical Discoveries and Collections -- Geological Fact -- Encke's Comet --

New method of Embalming -- Habits of the Flamingo in Patagonia.

A letter, addressed to the president of the Academy by Baron de Humboldt, at Berlin, was read at this sitting; it relates to the Baron's friend and travelling companion, Bonpland, who lately contrived to obtain his release from years of captivity in Paraguay.

"Above a twelvemonth had elapsed," says the Baron, "since we received the first intelligence of the arrival of M. Bonpland in the province of the Missions; but no letter from him had ever reached Europe, and his relatives at La Rochelle felt the same anxiety on his account which I did.

At length I have had the happiness of receiving direct news from him through the care of Baron Delessert.

A letter from Bonpland, dated Buenos Ayres, the 7th May 1832, advises, that he had received a few lines, which I had forwarded to him at the close of July last year, whilst resident at Corrientes, near the confluence of the Parana and Paraguay, in January 1832.

'I have been crossed,' says he, 'in every labour I have projected since I quitted the soil of France.

My ill stars have persecuted me for the last fifteen years; but I am fain to believe that my fate will prove more auspicious, now that I am out of Paraguay.

Being once more restored to my friends, and having renewed my connexion with civilized Europe, I have resumed my former labours in natural history with the greatest activity, in order that I may be enabled to return to my native country as quickly as possible.

The collections I formed in Paraguay and the Portuguese Missions ought to have reached Buenos Ayres ever since the month of March. I look for them with the greatest uneasiness, and shall forward them immediately upon their arrival, (which cannot be long delayed,) to the care of the Minister of Foreign Affairs at Paris, praying him to deliver over the cases to the Museum of Natural History.

The Jardin des Plantes will receive, not only what I have recently collected, but such herbaria as I have put together at Corrientes and Buenos Ayres, and particularly my general herbarium, and the geological series of the route we pursued.

To this collection I shall add the specimens of rocks which I have just collected, as well as such as I may succeed in procuring during my excursions to Monte Video, Maldonado, and Cabo-Santa-Maria. *** Such are the fertility of the soil and the richness of the vegetation in the Portuguese Missions, that I think it my duty to return to that quarter, and I am willing to believe, that those who kindly take an interest in my early return to Europe, will not disapprove this trip.

It would be cruel to leave this clime without adding such a host of remarkable productions to our botanical stores.

My collections will comprise two new species of Convolvuli, the roots of which possess all the healing qualities of the jalap.

I am in hopes that the School of Medicine will likewise set some essays on foot as to the uses to which three extremely bitter barks, derived from three new species of a class belonging to the family of the Simarouboeoe, may be put.

These barks are of the flavour of the sulphate of quinine, and are used with the most salutary effect in cases of dysentery and other gastric derangements.

If, whilst here, I could but receive proper information on the efficacy of these barks, as it might appear from trials in Paris, I would endeavour to secure a supply of them for our hospitals before my departure.' *** I avail myself of this opportunity," adds De Humboldt, "to communicate a geological fact to the Academy, which has been known here only within the last few days, and is connected with other facts, which have been observed elsewhere in Europe, and even in the heart of Asia. M.

Von Seckendorf has discovered fragments of Grauwakke, accompanied with petrifactions incrusted in granite, in the valley of Badan (of the Hartz), in a quarry near the high road which leads to Hartzburg. M. Hartmann, the translator of Lyell's Geology, has just confirmed this observation. --

P.S. At the very moment of closing this letter, I receive the very important information that Encke's Comet, of three years and three tenths, was observed at Buenos Ayres in the beginning of June 1832. M.

Encke has heard from M. Olbers (of Bremen), that M. Massotti (probably the same gentleman who was formerly at the Milan Observatory, and has published some works on planetary orbits), observed the comet at B. A. on the 2nd of June last, at 5h 30' mean time, with 56° 37' 5" of right ascension, and 11° 20' 1" of southern declension.--This observation appears to differ not more than some 2' from the short-period comet, which M. Encke has calculated by anticipation."