VOYAGE FROM NEW YORK TO RIO DE JANEIRO. 3 
than the western one, for the latter is chilled by the Arctic 
currents, which form a band of cold water all along the 
Atlantic shore. Their influence is felt nearly to the lati- 
tude of Florida. On coming out of the Gulf Stream the 
temperature of the water was 68, and so it continued for 
an hour longer, after which Mr. Agassiz ceased his obser- 
O ' O 
vations. To-day some of the gulf-weed was gathered by a 
sailor, and we found it crowded with life. Hydroids, in 
numbers, had their home upon it ; the delicate branching 
plumularia and a pretty campanularia, very like some of 
our New England species ; beside these, bryozoa, tiny com- 
pound mollusks, crusted its stem, and barnacles were abun- 
dant upon it. These are all the wonders that the deep has 
yielded us to-day, though the pretty Portuguese men-of-war 
go floating by the vessel, out of reach thus far. Such are 
the events of our life : we eat and drink and sleep, read, 
study Portuguese, and write up our journals. 
April 4th. It has occurred to Mr. Agassiz, as a means 
of preparing the young men who accompany him for the 
work before them, to give a course of lectures on ship- 
board. Some preparation of the kind is the more necessary, 
since much of the work must be done independently of 
him, as it will be impossible for so large a party to travel 
together ; and the instructions needed will be more easily 
given in a daily lecture to all, than in separate conversa- 
tions with each one singly. The idea finds general favor. 
The large saloon makes an excellent lecture-room ; a couple 
of leaves from the dining-table with a black oil-cloth 
stretched across them serve as a blackboard. The audi- 
ence consists, not only of our own company, but includes 
the few ladies who are on board, Mr. Bradbury, the captain 
of our steamer, Bishop Potter, some of the ship's officers. 
