6 



TRAVELS IN BRAZIL. 



ing specimens of all the natural productions of the 

 several kingdoms, as the best certificate of the ob- 

 servations made. 



In addition to these instructions, each particular 

 branch of study at the university had its peculiar 

 claims upon the industry and observation of the 

 travellers. With respect to mineralogy, they were 

 instructed accurately to observe the geognostic rela- 

 tions in which the different formations of the moun- 

 tain masses in general stand to each other ; their 

 succession, magnitude, thickness, and particularly 

 their dip ; and, farther, to examine the hitherto 

 problematical production of gold, of diamonds, 

 and other precious stones, as well as of all the 

 more important fossils. In physics, they were 

 to observe the declination and inclination of the 

 magnetic needle ; its daily variation ; the pheno- 

 mena of electricity, according to the several de- 

 grees of latitude and longitude ; the transparency 

 and colour, the phosphorescence, temperature, and 

 saltness of the sea in different regions, and at various 

 depths ; the temperature of the atmosphere ; the 

 phenomenon of the Fata Morgana; the mean 

 temperature and the differences of climate in vari- 

 ous parts of the continent ; the periodical oscillation 

 of the barometer ; the different elevations of the 

 ground ; the traces of the gradual receding or 

 advancing of the sea, on the coasts ; the currents, 

 the local anomalies in the tides ; the electricity of 

 the fish, &c. The historical and philosophic-philo- 

 logical classes of the university recommended 



