The Sun.
London, England, 1817-07-25 00:00:00

57F,‘\1 iiOAINJ.

•
Air. WiLLTLM CIIMMAN C,.12/ed in, and esarniftcd:
What is your 'profession, and pl.ice of abode ?
My phifessiop is dell enLineer ; general pLice
of abode is Newcasile-upon-Tyne.
Have you, as engineer, turned your sttentiou
to the construction of steam C11611C3 for steam-
lithos ?—As to the steam bo:;ts, I. have not parti-
cularly; but I !rave b.Len concerned in steam en-
gines of every description, from bei:l4 connected
with the collieries, where we have many engines.
Have you any steam boats upon the Tyne
We have.

[lave you seen those sham !.mats ?--Yes ;I
have.

How many have you ?--I think it is three ; bot
I have only been in one of them.
Do you know the con,truerion of the iteani
boats employed upon the Tyne ?—Low pressura
condensing engines.
Are you aware of any reason which would ren-
der it expedient to forbid the use of high pressure
engines ou board steam boats look upon
engines, whether high pressure or low pressure,
as dangerous to the passengers, unless due pre-
caution be taken to emit the steam when exceed-
ing a given pressure ; for in low pressure eugiueg
the boilers are always liable to burst or to alter
their forte, when,the pressure becomes superior
to the resistance ; all boilers but those that are
cylindrical in the section, and ki ith
ends or portions of spheres or cones Or COO,,IdS, ft.r
liable to alter the form by The natural expati.,ive
force of the steam, and therefore all boilers but of
those forms owe their safety to their ‘veaknessd,
because if weak they will alter their form without
danger, and if strong, they have been know(' to
bend the iron so abruptly as to break asta'ler.
Are you speaking of wrought or cast iron
speak of wrought iron ; and *consequently they
explode, and in many instances have destroyed se-
veral of the passengers ; they are so far more dan-
gerous to the passengers, that they frequently-
staid them, and do not actually kill them ; there
are a description of engines in use io,the'counties
of Durha In, Northumberland, Cumberland. and
York, that are termed loco-motive engines ;' -the
form of• their boilers is cylindrical, with curved
ends.

Are those applicable to boats ?—Certainly ;
they are pressure engines, working
_with a
force of from fifty to siity4ive pounds per inch,
and no accident has happened to any of them but
to one, the safety, valve of which was stopped hy
a man sitting upon it or holding it down purposely;
he said, " we will have a good start and s:lrnrize
them, we will go off so wdl ;"—the consequence
was, that the boiler blew up, and killed and
wounded a. very considerable number of people ;
believe to the extent of forty-five, but 1< am not
certain.

Was that a cast or a wrought iron boiler ?—it
was wrought iron.

Can you suggest t!,e means hy which a higit
pressure engine can be rendered sate on .
vessel )—lt can Only be rendered safe by hating
the form of the boiler, such MT I lirtre deacrityrti,
and the cylindric part of alimiTeddialneter, with-
a competent thickness of wroug!it eitio;r
iron or copper, and the plates secured to each
other by a double line of rivets ; it is also rcqui-
site that there should be two safety valves, evtert
laden with any determinate weiglit per sonerfcial -.-
inch of the narrowest part of the seat tit the valve;
one of those vales should be at perfect liherty •40
he raised at the pleasure of the manager, because .
some' idles it is expedient to raise it ; the otber,
should be under a cover of such de6Cript ion as. not
to he opened at all, at the discretion of the engi-
neer, hut with sotlicient apertures for the emissioa
of the steam, and for any of the passengers to sec
that the valve is not made fast. 11 is also rtzpai=..
site that there should be a mercurial gunge of aaa
less than an inch in diameter, and whose longest
limb shall not he greater than tivo inches and trne
eighth for every pound per inch •• upon the safer
valve ; it is necessary by occasional inspeeton tts
take care that the mercury does not stiffen' by
oxydation, occasioned by the heat and motion tt,
'which it is in a slight degree liable.
Do you conceive that a high presure engine
thus guarded might he used OM board a steam boat
with safety to the passengers ?—Yes, so long as
the boiler is kept in order but the boiler's bot-
tom is liable to erode or consume by the action of
the fire, cud therefore requires
boi'lveurixe,l:ir
would
d
—A boiler may last twelve
last un-
derlit°hlev aloctnigondoofyfior'et thick
a
months safely, provided its bottom be made of
charcoal iron, beat not rolled, because there is &
great deal of difference in the grain.
Wonld von not always recommend a boiler te+
be made of wrought metal on board stea.ru botsts.t
On board steam boats I would recommend_ them
all, to to be made either of copper or charcoal irott
plates beat under the hammer and flat th's
resistance of cylindric boilers will be in the in-
verse ratio of their diameters.

cr. be contint.d..l