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320, Safety Apparatus for Steam Boats. 
open, and when required ‘to be used to prevent the escape of all the 
steam, will be pressed down,’ as is usual, by a weight acting by the 
intervention of a lever. This apparatus should be so placed. upon 
the boiler as to be seen by the passengers, who are thus enabled to . 
know that all is right, while the lever attached to the valve is in an 
elevated position, showing that the valve is raised from its seat; this 
lever is kept in its raised position, by a cross bar, supported on up- 
rights, to which it is attached by a strong chain fastened by a pad- 
lock; the key of this lock being in the possession of the captain of 
the boat, the chain cannot be slipped, and of course the lever cannot 
be lowered, to close the valve, except through his agency. Suppose 
the steam or the boiler to become heated to the fusing point ‘of the 
plate; it melts, steam issues through the. small cylinder covering the 
plate, with a noise, which even at night would arouse the captain and 
passengers; if no danger will be incurred by loss of steam, and the 
consequent stoppage of the engine, such an escape should be allowed 
as a measure of precaution, though it is by no means one of neces- 
‘sity, since the limit of temperature producing fusion is much below 
that required for explosion. The alarm giyen, the steam gauges 
should derangement of the safety valve have prevented its action, OF, 
the usual practical observation upon the issuing steam, will show 
whether the fusion of the plate was caused: by an accumulation. of 
steam, or by the defective supply of water; this may be further 
tested by the guage'cock; should it prove that -the water is below 
the usual level, a supply can be introduced without danger. A se 
cond plate, arranged ina similar manner to the first, fusible at say 
20° F. above this, should be also provided, that the same means. 0! 
safety may remain in case of accident to the first plate. The vigi- 
lance of the engineer would almost be insured: by the use of these 
plates, from a knowledge that his inattention could not escape de- 
tection and its consequences. Passengers would be guarded against 
the results of carelessness, should it exist, and captains, as well as 
the public, would have the means of knowing accurately the value 
of those employed in the responsible station of engineers. The 
eaat of patronage which would inevitably attend an ill regulated en- 
gine, would soon correct evils now so formidable. 
~ By the annexed figures, the method of arranging the fusible plate 
and safety valve, is shown in detail. rr ; 
