RIO DE JANEIRO AND ITS ENVIRONS. 57 
hundred men, relieving each other alternately, have been 
at work day and night, excepting Sundays, for seven 
years. The sound of hammer and pick during that time 
has hardly ever been still, and so hard is the rock through 
which the tunnel is pierced, that often the heaviest blows 
of the sledge yield only a little dust, no more in bulk 
than a pinch of snuff.* 
On our return we were detained for half an hour at 
a station on the bank of the river Parahyba. This first 
visit to one of the considerable rivers of Brazil was not 
without its memorable incident. One of our friends of 
the Colorado, who parts from us here on his way to San 
Francisco, said he was determined- not to leave the expe- 
* This road, which is but the beginning of railroad travel in Brazil, 
opens a rich prospect for scientific study. From this time forward the difficulty 
of transporting collections from the interior to the seaboard will be diminish- 
ing. Instead of the few small specimens of tropical vegetation now preserved 
in our museums, I hope that hereafter, in every school where geology and 
palaeontology are taught, we shall have large stems and portions of trunks 
to show the structure of palms, tree-ferns, and the like, trees which represent 
in modern times the ancient geological forests. The time is coming when our 
text-books of botany and zoology will lose their local, limited character, and 
present comprehensive pictures of Nature in all her phases. Then only will 
it be possible to make true and pertinent comparisons between the condi- 
tion of the earth in former times and its present aspect under different zones 
and climates. To this day the fundamental principle guiding our identification 
of geological formations in different ages rests upon the assumption that each 
period has had one character throughout ; whereas the progress of geology is 
daily pressing upon us the evidence that at each period different latitudes and 
different continents have always had their characteristic animals and plants, if 
not as diversified as now, at least varied enough to exclude the idea of uni- 
formity. Not only do I look for a vast improvement in our collections with 
improved methods of travel and transportation in Brazil, but I hope that 
scientific journeys in the tropics will cease to be occasional events in the 
progress and civilization of nations, and will be as much within the reach of 
every student as journeys in the temperate zone have hitherto been. For ''nr- 
ther details respecting the building of this road, see Appendix No. IV. L A. 
