Safety Apparatus for Steam Boats, 319 
should thus, by borrowing from our brethren abroad, be provided 
with a certain remedy against explosions caused by the circumstances 
we have endeavored to explain, and also against the bursting of the 
_ boiler from an accumulation of steam within, should any accidental 
derangement of the common safety valve preventits action. This de- 
vice would be of the greatest value if applicable to steam boat boilers, 
for, being entirely without the control of the engineer, caution would 
be produced by the fact that any attempt to raise the steam above 
the proper pressure, or any inattention to the supply of water within 
the boiler, would be immediately made known to the captain and 
passengers by the noisy effluxof steam through the aperture opened 
by the melting of this tell-tale plate. If the plate were placed within 
sight of the passengers, the only means of an improper kind, to 
which the engineer-could resort, to prevent. its fusion, (sometimes 
practised in the stationary engine in F rance, according to M. Arago,) 
viz. keeping it cool by the application of water to its surface, would 
| be entirely cut off. ‘ 
The reason why this plate has been considered inapplie le to 
‘Steam boat boilers, in general, is obvious; when the plate all 
the steam must escape from the boiler, and the apparatus must cool 
_ before it can be replaced by a similar plate ;. this sudden desertion of 
_ the prime mover of the engine might, in certain cases, put the lives 
‘of the passengers in almost as great jeopardy as an explosion; in- 
stances, in an exposed navigation, will readily occur on reflection, 
such as a boat on d lee-shore, &c. In all cases such a. desertion 
Would be attended with very great inconvenience. ” 
The remedy for this, and one which simplicity and consequent 
fase of application seem to recommened very particularly, will now 
beistated. If, as is hoped, this apparatus shall be found to remove 
every objection to the use of the fusible plate in the boilers of steam 
oats, it will insure the exemption of passengers from a portion at 
least of the dangers to which they are now so often exposed... i 
The method, which I would propose, is to combine the fusible 
Plate, with the ordinary safety valve. Such a plate affixed to an 
Opening of a proper size, in the boiler, as near as may be practicable 
o the highest line which is exposed to the direct action of the fire, 
'S Covered with a hollow cylinder, of a greater diameter than the 
aperture covered by the plate, the base of which presses upon the 
edges of the plate, while the top is arranged as the seat for a coni- 
cal, or flat valve, of the ordinary kind ; this valve will be habitually 
z¥ 
we 
