The Madisonian. [volume] (Washington City [i.e. Washington, D.C.]) 1837-1845, 1838-08-22
From The National Gazette.
BOILERS No. 8.

DOlLEno NO D.
II has generally been customary 10 works protesting
TO treat OF the Steam Engine. embrace IN desenp
ton Of the boiler accounts OF oil It's appendages and
sometimes include, aso whatever relates to rs con.
tents and acton,--its dangers and the means of OF.
WAITING them The boiler itself however, being Of para.
mount importance, at once the and the reser
yor Of power, aud having many points OF character
necessary TO be understood IN order 10 full compe
henson Of its action, will is conceived be properly
considered apart from the other matters just enume.
rated
We know not that we could better Sc, forth the rpa
for separate consideration of the boiler and offs
contents than in the language Of the opening paragraph
IN report ON the strength Of materials for boilers
submitted some months since TO the committee OF the
Franklin Institute Explosions, and through that body
to the Secretary Of the Treasury and BY him laid before
Congress.
while it is important 10 know the causes which
may produce dangerous development Of elastic forces
in the interior Of obviously not less
TO understand Alright the efficacy Of those means on
which we rely for con6ning controlling their
ges Hence, IN investigating the of explosions
is both natural and expedent examine separately
those facts and principles which concern the dire
and the qnieseent forces respectively The number
and variety Of circumstances which affect the charac.
ter and durability Of materials Of which steamboilers
formed, probably not less than OF those which
tend 10 modify the action of the fluids which they con-
tain In this view of the importance be attached TO
the subject Of the strength Of materials. may be con-
sidered remarkable, that while investigations
have been made to the Of danger, little
should have been attempted regard 70 the most direct
and obvious means of security"
The scientific Investigations relative to the boiler
have had reference TO other particulars hesides
the mere sirength Of the materials which compose it,
and may be comprehended under the following partcu-
lars:
]. The tenacity Of wrought and cast iron and cop.
The elasticity Of the same metals and the force re.
CURED to produce permanent change Of form or d.
mension.
s. Their e1tensihility by mechanical strain under
different circumstances and in different directions
g. The effect Of the direction ofrollng on the strength
Of the same material.
g. The influence Of temperature on tenaci,y
2. Effect OF the process Of snnesling the strength
Of rolled iron.
Effect Of long and repeated use on the tenscity Of
metals.
8. Strength Of boilers as dependent on then forms,
dimensions and thickness.
TO- Effect Of the modes employed for connecting to-
gether the different parts composing boiler.
H. The tests to which boilers should be subjected
and the methods Of proving them.
H. The conducting power OF The metals for heat
ID The specific heat Of the metal OF boiler which,
combined with ITS weight, affords the cf ascer-
tanning the quantity Of vspour which might produce
tempe natures
With the exception Of the 9th, lih and 9Th OF the
above topics, a less extensively treated
the report above referred The OH had been pre-
yiousy examined in not altogether general it
is true, by Oliver Evans, in his Young Steam Engi-
neer's Guide !" by Mr. A. B. Qunby IN maihe,naii.
cal solution relative 10 the curved surfaces of cyludr
ca: boilers, contained in the American Journal Of Sci
encc, vol g. and in the by another writer
IN paper IN VOL 23d of the Journal in which the
forces, necessary 10 retain any given pressure are de-
tenned whether that pressure DO exerted against the
head sides Of boiler The formula Of the French
ordnance mentioned in former article, may be also
again referred 10 in this connection. II assumes that
boiler ought to have given constant thickness indie
pendent OF that which the pressure within would require
for an assumed diameter and also to increase in thick
ness for given diameter rapidly than the pres
itself increases This must be upon the presump-
ton that tenaciy dimnshes rapidly by heat than
the tension Of steam increases by the same mems
The constant thickness which required 10 be given to
every boiler Of whatever diameter and pressure is
about IL 100 Of inch and each boiler must have be-
sides thickness at least nine times great the metal
would require, for sustaining The assumed pressure its
total tenacity.were brought into action All these re-
QUESTIONS give, doubtless, when iron 10 employed. an
thickness, will be more fully apparent
when we come to examine the results Of researches on
lenacity.