For two days we made our way up a good-sized river some hundreds of yards broad, and dark in color, but transparent, so that one could usually see the bottom. The affluents of the Amazon are, half of them, of this nature, while the other half are whitish and opaque, the difference depending upon the class of country through which they have flowed. The dark indicate vegetable decay, while the others point to clayey soil. Twice we came across rapids, and in each case made a portage of half a mile or so to avoid them. The woods on either side were primeval, which are more easily penetrated than woods of the second growth, and we had no great difficulty in carrying our canoes through them. How shall I ever forget the solemn mystery of it? The height of the trees and the thickness of the boles exceeded anything which I in my town-bred life could have imagined, shooting upwards in magnificent columns until, at an enormous distance above our heads, we could dimly discern the spot where they threw out their side-branches into Gothic upward curves which coalesced to form one great matted roof of verdure, through which only an occasional golden ray of sunshine shot downwards to trace a thin dazzling line of light amidst the majestic obscurity.