Account of Travels lehveen the Tropics. 35 3 



still present, the ammonia will produce a blue colour in the 

 water. The silver, if not wished to be kept as a powder, 

 may be melted with from a fourth to a half of its weight of 

 nitrate of potash. 



The liquid sulphate of copper decanted from the precipi- 

 tate, as also the water employed in washing it, may after- 

 wards be evaporated in a copper bason, and, by crystalliza- 

 tion, a quantity of blue vitriol equivalent to the cost of the 

 acid will be obtained. 



Should some parts of the alloy, by accident, have re- 

 mained undissolved, they may be separated by decantation, 

 and reserved for the next repetition of the process. 



LX. Short Account of Travels between the Tropics, ly 

 Messrs. Humboldt and Bonpland, in 1799, 1800, 

 1801, 1802, 1803, and 1804. By J. C. Delame- 



THERIE*. 



X HE interest which the learned world so justly takes in 

 the travels of Messrs. Humboldt and Bonpland, as well as 

 my friendship for them, impose on me the agreeable obli- 

 gation of giving an abstract of what I have been able to 

 learn respecting them, cither fi'om their p.ublic and private 

 correspondence, or from the memoirs read in the Institute. 

 This account will be short, but correct. 



After making physical researches for eight years in Ger- 

 many, Poland, England, France, Swisserland, and Italy, 

 M. Humboldt came to Paris in 1798, where the Museum 

 of Natural History afforded him an opportunity of making 

 a voyage round the world with captain Baudin. When on 

 the pomt of setting out for Havre, with Alexander-Aime 

 Goujou Bonpland, a pupil of the School of Medicine and 

 Garden of Plants, the war which recommenced with Austria, 

 and the want of funds, induced the Directory to put off the 

 voyage of Baudin till a more favourable occasion. M. Hum- 

 boldt, who since 1792 had conceived the design of under- 

 taking, at his own expense, a voyage to the tropics, in order 

 to promote the physical sciences, resolved then to accom- 

 pany the men of science who were destined for Egvpt. The 

 battle of Aboukir having interrupted all direct conmmni- 

 cation with Alexandria, liis plan was to take advantage of 

 a Swedish frigate which was to carry the consul Seziolde- 



• From Journal Jr Pbysiqiif, Thcrmidor, an ji. 

 Vol. 21. No. 84. May 1805. Z brant 



