Year: 1870

The reason why the rivets of steam boil
ers are more apt to crystalize and lose
their heads, is important, in order to select
the best mode of preventing the result.
Crystalization is inevitable in proportion
as polar or @rial or magnetic force. Gall
of which are the same) preponderates over
gravity the attraction of adhesion-caplla-
ry attraction-and the attraction of cohesion,
which are not all the same, and may an
tagonize it. Consequently whatever aids
in bringing about, or increasing, this pc
culiar sort of attraction, or removing the
obstacles in its way, may be regarded as
promoting crystalization and the explo-
sion of boilers when this result manifestly
depends on the loss of the heads of rivets
and it is satisfactorily demonstrated that
those were originally made of the most
tough and perfect iron. Whereas now it
is crystalline and brittle. 1.-The particles
of the most dense steel are never in con-
TACT" otherwise it could never be reduced
in bulk by q reduction of temperature,
each atom may be supposed to revolve in
its own cell of space as the world-having
like it q north and south pole-produced
in the same way, why a current of e.
lectricity from east to west-but capable
of increased or diminished velocity and
consequent " Wis viva" and also polarity.


Tough iron is composed of threads of
atoms like string of beads, viz: atoms
bound together as iron filings are arranged
when Lode-stone is placed beneath the
paper ON which they are spread-the north
pole of one molecule being attracted to the
south pole of the next particle-but this
illustration also exhibits the other idea,
ziz: that polar force actually. overcomes
the force of gravity, &c. and determines
certain molecular arrangements indicating
the outlines of crystals such as appear on
the window pane, from precisely the same
cause in cold weather. And also in the
rivets when their heads fly off, so also the
iren filings are projected from the paper in
beautiful crystalline forms before the Lode
stone touches the paper, although the un
der surface of the paper over which the
filings are scattered is exposed to its
influence If while bound together as
strings or threads of particles as thus de-
scribcdTrthey could also be cemented and
woven like cloth-they would form tough
iron as much in contrast with homogene-
GUS or common iron as shoddy is different
from good cloth, although composed of the
same material.


Nevertheless this '' long staple cloth
in the case of the tough iron, retains its
disposition to regain the original crystal
line arrangement of these threads more
over, as this result of polar or aerial force
is enormously increased, (viz in proper
tion to 1.-THE square") by proximity any one
can easily conceive of its ultimate prepon-
derance in rivcts peculiarly constituted, as
above by this force, present and active in
their fbres, bearing seven times as much
of the strain as the boiler iron and also
compressed by the oxidation of their sur
face, but sometimes afforded chance for
molecular arrangement by the extreme
changes of temperature. Upon the same
principle the familiar fact, that the nails
become more tough by use in horse shoes,
can be accounted for, their fbrous or tex
tile character being improved and perJec-
ted without any chance for an increase OF
the erial or crystalline force over the
other forces which are capable of direc-
ting its developement and using it in pro-
noting their cooperation. Recognizing
the causes. we may thus have an indica-
tion of the remedy for this fruitful and
subtle agent in boiler explosions.


DAVID STEWART, NJ. D.


Port Penn, Del.