The sun. [volume] (New York [N.Y.]) 1833-1916, 1899-09-03
SCIENCE OF MICRO-METALLUHGr.
New Method of Studying the Structure of
Bronzes Used In Machinery.

BronZes Used in Machinery.
Alexander L. Outerbridge. Jr. a metallurgi-
cal expert Of Philadelphia, has recently been
making some experiments in the new science
OF micro photography with the object of dis
covering by careful study OF tho micro
structure OF bronzes why an axle bearing
will sometimes cut out" In a short time
and another. not differing from it in any
way that the naked eye can detect. may last ten
times as long. The solution OF this problem is
Of great importance to railroads and manufac-
turerS. Mr.. Outerbridge ia the metallurgist Of
the Sellers tool works. Philadelphia. He said
OF his experiment:
THE microscope has long been employed in
the examination of minute forms OF life. and
OF the structure OF leaves. flowers thin and
transparent sections Of woods. materials and
other objects. More recently the powerful eve OF
the microscope has been called to the aid of the
metallurGist in pecring into the arrangement
OF molecules OF metals. A coin, fresh from the
minting press. presents to the naked eve
beautifully polished. smooth surface. but when
examined under strong magnifying glass
shows many defects. The surface Is seen To
be tu OF pits. or small holes. and other sur
face irregularities. while tho design looks
coarse and crude. This Is quite natural and
1t is only to he expected that a very moderate
magnilcntlon will show these defects Within
ihe past score OF years scientific men in Europe
and this country have been delvinR deaper
than ever before into the mysteries OF the
molecular structure OF metals, by the mid Of
powerful microscopes. assisted by photos
ranhy
In my cXpe riments on the micro-structure
-of hronZcS was assisted BY Fred T. Mnisnh
son OF the late Pro-, Maisch. the well-known
r pohhniN' %ho Is an expert micro-photog-
hriHht new copper cent the surface of which
ia 3ruer 10 prnpery study and photograph its
molecular structure, we flied and ground ms
moN" al scratches after which the coin was
creme IN acld IN order to develop the CRYSTAL
Im" structure OF the alloy, Alter This treat
surface examined by the mirroscupe unjer n
strong light. By substituting u camera Tor The
eye ana i"cussing the image upon tn" senSi-
,,"',n nt,a't W. ontllheh micro. photograph
manner. "'o"'
=. The general appearance OF the picture Of
fno III 'Honi rnSrd o' COPPER tin and zinc
OF a neld which has been ploughcd ana then
narrowed ana rNked This Is the micro.
S nr mt si%rrn,led OF metals: large num-
subjected to this method OF examination,
mes i ntsn were cur from as mnnv castings. the
immediate practical object being 10 ilnd out. il
dense aud homogeneous than others md
therefore NOR" durable when subjected To-
wear, or more suitable for cylinders in which
steam Is conIincI under high pressure ar Tor
hyirhull" WORK. We have mad, prnrrr.s win
our work ana expect definite aud decisive re-.
Mr, OuterhridGC recently delivered an adj
dress on mcTo-p photography before the min
iIE ana metaurRlcal section Of the Franklin
INSTITUTE, Philadelphia, which attracted n
iecs frn ali o1r oi sSperts Interested in the sub
were OF the opinion that he is on the track ~
important discoveries va '"' 'iaeA VI