44 



head an English convoy, which sailed along the 

 coast, steering towards the south east. In order 

 to avoid it, we altered our course during the 

 night. From this moment no light was permit- 

 ted in the great cabin, to prevent our being seen 

 at a distance. This precaution, used on board 

 all merchant- vessels, and prescribed in the regu- 

 lations of the packet-boats of the royal navy, 

 was extremely irksome to us during the passages 

 we made in the course of the five following 

 years. We were constantly obliged to make 

 use of dark lanterns to examine the temperature 

 of the water, or read the divisions on the limb 

 of the astronomical instruments. In the torrid 

 zone, where twilight lasts but a few minutes, 

 our operations ceased almost at six in the even- 

 ing. This state of things was so much the more 

 displeasing to me, as from the nature of my 

 constitution I never was subject to sea sickness, 

 and feel an extreme ardour for study during the 

 whole time I am at sea. 



A voyage from the coast of Spain to the Ca- 

 nary Islands, and thence to South America, is 

 scarcely attended with any event which deserves 

 attention, especially when undertaken in sum- 

 mer. The navigation is often less dangerous 

 than crossing one of the great lakes of Switzer- 

 land ; I shall therefore confine myself in this nar- 

 rative to the general results of the magnetic and 

 meteorological experiments, which I made in this 



