y ae, = & io 
334 Review of Renwick 
in the literal meaning of the word, would be useless; but when the 
firemen wish to urge their fires more than usual, they understand 
how to prevent the fusion of the plate, by directing a constant stream 
of cold water 4 it, so that in ) this point of view, perhaps we have 
gained nothing.’’* 
_ We have extracted this passage at length from the essay of | M. 
'  Arago, because it: appears to us that the subject of fusible metal 
valves has not commanded among our countrymen the attention it 
deserves. We do not learn indeed, that-a single trial has yet been 
made of them. And surely, the repeated and melancholy instances 
of steam boat explosions, that have occurred among us during the 
t two or three years, ought to awaken our attention to any’ de- 
for securing safety, eapucislly when recommended by authority 
so ob feipeotalo as that of M. Arago. There is some reason to fear 
a growing apathy in the public mind on the subject of steam boat 
accidents, from the very frequency of their occurrence. Those 
rho have often escaped, while others have fallen, fancy themselves 
ike veteran soldiers, invulnerable. 
Professor Renwick recapitulates the chief precautions to be em- 
ployed in order to insure safety, in the following paragraphs. Seve- 
ral of them we have already mentioned incidentally, but the impor- 
tance of the subject induces us to extract this passage entire. fe 
aay _ Cylindrical boilers, without any return flue, either without ig 
within, are safer than any others. 
2 Internal flues should be avoided whenever it is “possible; and es- 
pecially the chimney, or vertical flue, should never be permitted to 
‘pass through the boiler. 
Ea 3. Every boiler should be furnished, in addition to the safety valve, 
- with one not under the control of the fireman. 
4. All boilers should be furnished with guage cocks, or other appa 
ratus, to show the level of the water, and these should be so placed in 
steam boats, that no error in their indication can take place gc the 
vessel heels or rolls. 
5. Plates of fusible metal sould be provided. 
6. A thermometer should be ea into the boiler, whose in 
dications may be seen from 
7. Self acting feeding appa sabia be ada ted to the boned 
_ by which water will enter, and keep shenaiea Within at 3 Or ae 
level, and this should depend upon thi e waste of water, and not on} 
scot the engine. It unluckily happens that no na ?—, 
a 7 bg on te Hsposon of Bein Fak il V Volver. 
rc ae = 2 
- 
“a 410. io ¥ 
