LIFE IN RIO CONTINUED. 95 
that of Miiias Geraes. A survey of the Dom Pedro Rail- 
road, made under his direction by his two young friends, 
Messrs. Hart and St. John, is also an excellent beginning 
of the work in this department, and his own observations 
on the drift phenomena have an important bearing on 
the great questions on which he hoped to throw new 
light in coming here. The closing words of a lecture 
delivered by him last evening at the Collegio Dom Pedro 
Segundo will best express his own estimation of the facts 
lie has collected in their bearing on the drift phenomena in 
other parts of the world. After giving some account of 
the erratic blocks and drift observed by him at Tijuca 
and already described in his letter to Mr. Peirce, he 
added : " I wish here to make a nice distinction that I 
may not be misunderstood. I affirm that the erratic phe- 
nomena, viz. erratic drift, in immediate superposition with 
partially decomposed stratified rock, exist here in your 
immediate neighborhood ; I believe that these phenomena 
are connected, here as elsewhere, with the action of ice. 
It is nevertheless possible that a more intimate study of 
these subjects in tropical regions may reveal some phase 
of the phenomena not hitherto observed, just as the in- 
vestigation of the glacial action in the United States has 
shown that immense masses of ice may move over a 
plain, as well as over a mountain slope. Let me now 
urge a special study of these facts upon the young ge- 
ologists of Rio, as they have never been investigated and 
their presence is usually denied. If you ask me, ' To 
what end ? of what use is such a discovery ? ' I an- 
swer, It is given to no mortal man to predict what may 
be the result of any discovery in the realms of nature. 
When the electric current was discovered, what was it ? 
