444 A JOURNEY IN BRAZIL. 
may reduce the vigor of the constitution, and perhaps make 
one more liable to certain diseases ; but during our journey 
of eight months none of our large company suffered from 
any serious indisposition connected with the climate, nor 
did we see in any of our wanderings as many indications of 
intermittent fever as are to be met constantly on our West- 
ern rivers. The voyage on the Amazons proper has now 
become accessible to all who are willing to endure heat and 
mosquitoes for the sake of seeing the greatest river in the 
world, and the magnificent tropical vegetation along its 
shores. The best season for the journey is from the close 
of June to the middle of November, July, August, Sep- 
tember, and October being the four driest months of the 
year, and the most salubrious throughout that region. 
We had a rough and boisterous passage from Para to 
Ceara, with unceasing rain, in consequence of which the 
decks were constantly wet. Indeed, the cabins were not 
free from water, and it was only by frequent bailing that 
the floor of our state-room was kept tolerably dry. At 
Maranham we had the relief of a night on shore ; and Mr. 
Agassiz and Major Coutinho profited by the occasion the 
following morning to examine the geology of the coast 
more carefully than they had formerly done. They found 
the structure identical with that of the Amazonian Valley, 
except that the formations were more worn down and dis- 
turbed. We arrived before Ceara at two o'clock on Sat- 
urday, March 31st, expecting to go on shore at once ; but 
the sea ran high, the tide was unfavorable, and during the 
day not even a "jangada," those singular rafts that here 
take the place of boats, ventured out to our steamer as 
she lay rocking in the surf. Ceara has no harbor, and the 
sea drives in with fearful violence on the long sand-beach 
