292 Securities against Fire, &c. 
As to the fall of the dome which covered a lofty building, lately 
erected near London, and where it does not appear that there was 
any fire; if the dome was defective neither in its form nor in its archi- 
tectural construction, it may be asked whether the iron contained in 
its frame in the parts exposed to the sun, was not preternaturally 
heated, compared with other parts not so exposed ; and whether this 
did not cause a distortion in the whole of the fabric; or in other 
words, did not cause a rupture in some parts, not to be resisted, which 
was followed by the downfall of the dome. 
The preceding seven articles in this supplement have had reference 
to circumstances connected with conflagrations. 
and 15.)—8. Datum. The first explosion instantly or within three minutes followed 
this noise. The second explosion followed very closely, ‘lapping on to the first.” 
(15.)—9. Datum. It is not said in what manner “the few square feet of iron plate 
were connected with the copper parts of the engine ;” but it is plain, that the chan- 
ges in the two metals were not exactly of corresponding natures.—10. Datwm. The 
second explosion may have been aided by the sudden generation of steam, conse- 
quent upon the water being thrown (during the commotion which things soon un- 
derwent) upon heated copper, capable of generating an “ uncontrollable quantity of 
steam ;” which steam had to passa tube of 20 feet in length and 10 inches in diam- 
eter, before it reached the safety valve—11. Datum. The copper was bent in 
parts in an extraordinary manner ; thatis, folded in massy doublings like a garment. 
In other words, the copper may be supposed to have contracted its dimensions = 
that is, I think we may say that in the case of the copper of the boiler, it was not 
merely ruptured ; especially as the body of water and of steam may be supposed to 
have given an even distention to the copper from within. (See report p. 5 and other 
places.)—12. Datum. We may conclude, that it will in future be wise to direct, 
that all the connected parts of the steam engine containing water or steam, should be 
made out of one metal: and that such other precautions should be taken as to steam 
engines in steam boats, as foreign governments (English and French) have discover- 
ed by experience to be preventive of mischief We add, that a strong suspicion is to 
be entertained, that the safety valve was not sufficiently attended to, during the stop- 
page of the steam boat New England at Essex ; and it is clear, that the door of the 
furnace was not closed, but was left open so as to admit the entry of air to increase 
the heat. Under these circumstances, the boiler, &c. had not a corresponding 
strength. 
To the above Data collected from the interesting Report on the cause of the ex- 
plosion of the boiler of the steam boat New England, we add the following particu- 
lars from Mr. Dalton. 1. Iron expands nearly one eight hundredth part in length 
or 265 part in bulk by 180° of Fahrenheit. 2. Iron is to copper in expansion as 2 
to3. 3. Although Mr. D. differs from Mr. Smeaton on these subjects, it is because 
Mr. S. has omitted some points in his calculation, and not because he was incorrect- 
4, We mention by the by, as something curious, that Mr. D. places the greatest 
density of water at 36°. Fahrenheit, and not at 40°. See new system of Chemicaf 
Philosophy, Part I. pp. 28—33, and 43. N.B. Itis unfortunate that the expan- 
sions of metals have not been tried beyond the temperature of 180° of Fahrenheit. 
