~ 
208 Miscellanies. 
by the surrounding water, which would greatly add.to the health and 
comfort of those on board. This result was also experienced on 
board the iron steamer already referred to, which went to Africa. 
Another advantage, which will be fully appreciated by those accus- 
tomed to voyages in tropical climates, is the entire freedom from in- 
sects and other animals which overrun wood vessels, forming in fre- 
quent instances, a perfect barrier to all comfort. 
9. Tron steamers are Jess exposed to accidents than wood steamers ; 
if the latter for instance touches the ground but slightly and only to 
rub her copper, which is often the case, it is absolutely indispensable 
in tropical climates, to have it immediately replaced, or otherwise a 
few weeks will be sufficient for the worms to destroy that part of the 
bottom so exposed. The expense attendant even on such slight re- 
pairs, particularly in the absence of docks, would be immense. In 
an iron vessel, under the same circumstances, no difficulty would 
arise. Again, an iron vessel in striking a rock, would very likely 
suffer an indentation in her bottom, but it would not pass through the 
iron, when a wood plank, under similar circumstances, would, in all 
probability, be broken and rent. An iron vessel has been thrown on 
a ledge of rocks, and after beating on it for some time, was saved ; it 
was found that the bottom was greatly bruised and indented, but still 
perfectly tight, and it was admitted by the spectators that a common 
wood vessel, under similar cireumstances, would certainly have bilged 
and gone to pieces. The iron bottom presents a perfectly smooth 
surface, the heads of the rivets forming a plane with the plates. 
10. It is, I believe, an understood principle, that superior buoyancy 
~ makes a superior sea boat, and its application is strong proof in favor 
of iron vessels for steam purposes. We have the united testimony of 
many persons who have witnessed the operation of iron steamers 
heavy weather, as to their great safety and security. It has been argued 
-by some that this very buoyancy rendered them unfit for high sea use. 
This argument naturally carries one back to about twenty five years 
~ ince, when it was considered indispensable, that a vessel of three 
hundred tons should draw seventeen or eighteen feet of water, to en- 
able her to hold a good wind and make her safe in a sea way- 
present the American packet ships of seven to eight hundred tons 
seldom draw, when in their best trim, more than thirteen feet of W® 
AL it has been urged against iron steamers, that they are subject t0 
extensive vibration by the action of the machinery. I was recently 
on board the Rainbow, (an iron steamer of one hundred and ninety- 
tight feet length, twenty-five feet beam, and nearly of six hundred 
*) onan experimental trip from Blackwall to Gravesend and back- 
