28 
of copper, it would perhaps be desir- 
able, in all cases where steam-engines: 
are applied to vessels, to. make the 
boilers of copper instead of iron-plate. 
Cast-iron boilers are now very properly 
almost abandoned, from their greater 
liability to fracture. It is also scarcely 
possible to obtain iron-plate which shall 
be of equal purity and tenacity to any 
considerable extent, independent of the 
liability to defect in some of the nu- 
Toerous rivets required in a large boiler. 
The tenacity and ductility of copper 
being so much superior, while it is not 
so rapidly corroded by the fire, renders 
copper-boilers infinitely preferable, both 
for durability and safety. 
The steam-boilers should also be 
provided, in every case, with two or 
more safety valves, of a sufficient size 
to prevent the possibility of explosion; 
and the regulating weight should be 
secured from the controul of the work- 
ing engineer by a lock and key. It 
would also be desirable to have a re- 
gister or indicator attached to the throt- 
tle valve of the steam-pipe, with a dial 
plate and index placed in some conspi- 
cuous situation, so that any passenger 
or spectator might at all times be ena- 
bled to see the degree of pressure at 
which the engine is working. The 
aperture of such valve, when fully open- 
ed, should not be more than sufficient 
to work the engine at a given pressure 
(say 60lbs. to the inch), by which means 
the liability to damage in the gear and 
paddle-wheels would be in a great mea- 
sure prevented, Whilst, in case the 
fire of the boiler should be injudiciously 
or wantonly urged, in order to increase 
the elasticity of the steam, it would 
escape by the one or more large safety 
valves, which would be placed out of 
the control of the engineer. 
In using sea-water for the formation 
of steam, there is also a considerable 
deposit of alkaline and earthy matter 
at the bottom and sides of the boiler, 
which, if suffered to accumulate and 
adhere to the boiler, has the effect of 
preventing the generation of steam, 
while it renders that part of the vessel 
more liable to destruction from the 
action of the fire.. The melancholy ac- 
cident that happened with the. Kitna 
steam-vessel, of New York, by which 
so.many lives were lost, a few months 
back, affords an additional proof that 
the utmost caution and attention is 
necessary on this part of the subject. 
From the statements given subsequent 
to the occurrence, it appeared that no 
Remarks on Steam Navigation, &c. 
[Feb. 1, 
blame. whatever could be attached to. 
the superintendant of the engine. The 
boat, at the instant of the explosion, 
was apparently only worked. by a pres- 
sure sufficient to give her paddle-wheels 
eighteen revolutions ina minute ; whilst 
her usual rate of working was twenty~ 
two or twenty-three, during so long a 
eriod as nine or ten years. The boilers’ 
lof which there were three in this ves-: 
sel)had also been examined and cleansed, 
only a few days previous to the explo- 
sion, and deemed perfectly secure. But 
on examination subsequent to the di- 
saster, it was found that the feed-pipe, 
which supplied the boiler with water, 
was completely choked up by a hard 
stony substance deposited from the 
sea-water. The explosion, therefore, in 
all probability, occurred in this instance 
for want of steam, or rather for want of 
a supply of water to keep the area of 
the boiler from acquiring a dangerous 
heat. 
The great superiority of the high 
pressure engines over the condensing 
engine, on account of the reduction of 
bulk and weight, with a vast additional 
power gained, renders them peculiarly 
adapted for steam navigation: but it is 
essential that they should be construct- 
ed under the most rigid inspection, and 
worked with more attention. than is 
usually to be found among ordinary 
engineers. : 
On account of the numerous acci- 
dents which have occurred from. the 
use of these, it was in contemplation 
a few. years back to restrict vessels, by 
Act of Parliament, to the use of low- 
pressure engines. But a Committee of 
the House of Commons very judiciously 
recommended the Legislature not to 
sanction such prohibition; considering 
that, inthis country, it would interfere 
too much with the freedom of commer- 
cial enterprize. 
The French Government also, about 
twelve months since, ordered a com- 
mission to be appointed, to inquire’ 
into the causes of explosions in steam- 
engines generally. And, although the 
steam-engine had at that period scarce- 
ly been introduced in France, the Com- 
mittee, of which the celebrated M. Du- 
pin was a member, made an able report 
on the subject, and recommended that 
competent inspectors should examine 
every steam-engine manufactured in 
France. That the boilers should be 
proved previously, and additional valves- 
applied to them ; which valves, together 
with the working of the engine, aa 4 
e 
