New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-12-11
MAGNETISM IN BRICKS.
INTERESTING EXPERIMENTS MADE AT
THE UNIVERSITY OF ROCHESTER,
MAGNETIC POWER ENOUGH TO VITIATE DELL
CATE EXPERIMENTS MADE IN BRICK
LABORATORIES.

when completed will be of immense value 10 the
constructors Of buildings and rooms designed
Dor the accommodation Of delicate instruments
fbr nice measurements in magnetism and
electricity. and which also will explain the
many mysterious instrumental and de-
nectiOns which have appalled, expermenters In
those lines
The subject Of this careful study has been
paain, homey bricks: and the results aston
hhing. The work has been done by Professor
Henry f. Lawrence. head OF the department Of
electricity. assisted by Otis Amsden Gage. Of
Rochester. who is taking a special course in
electricity They have discovered that almost
an the common bricks used for constructive
purposes magnets. and that many Of them
are Of sufficient strength to defect crude cleo
tic instruments to an extent appreciate TO the
naked eye.
What called Professor Lawrence's attention
b the possibility of magnetism in bricks
popularity he noticed in the actions of mag
netometer in the course of an experiment he
vas making in the basement Of the laboratory
two years ago. AT the time he at loss to
account for it, Last spring he visiting a
friend at Ann Arbor. and to his surprise was
Informed that precisely the same kind Of dis
turbance had been noticed there This friend
said half jokingly that he fancied it must have
come from the bricks. Professor Lawrence re-
membered that he had made his experiments
over brick pier to give the instruments per-
feet stability The conclusion he reached
startled him. AS soon as he returned to Roch-
ester he began to investigate the matter He
tried a brick against magnetometer To his
surprise the delicate needle backed away. He
tried another and the needle backed further.
He reversed the bricks side for side, and the
needle futtered a moment and then drew up
The bricks were magnets This discovery made
him resolve to pursue the Investigations farther.
He called in the aid of Mr.. Gage. and the two
went to work to prove their hypothesis. The
later experimentation was done by Mr.. Gage
Bricks are of two kinds, the pressed and the
common or baked brick. Samples of all kinds
were secured from the manufacturers. OF which
there are many in and about Rochester. In all
Mr.. Gage examined fifty specimens. Computing
the moment Of each brick as magnet Mr..
Gage plotted a curve deneatng the relative
strength Of each. He found that dark, mot
tied brown pressed brick manufactured near
Rochester possessed the largest amount OF force.
Next to that came a dark pressed brick mace IN
Washington A series Of red baked bricks all
gave the same results, being about medium In
their effect the needle. A yellow and white
brick also pressed gave but little PROOF OF
magnetic influence while the Harvard brick. OF
which the Harvard laboratory Is constructed.
was fifth in point Of strength.
On a scale Of 100 the notified red brick would
reach about 50, the white pressed brick from
Washington rs, the Harvard brick 81, and the
other bricks between and 20. The brick which
possessed absolutely no magnetism came from
a ward near this city. 1t is white in color. Inc
strongest brick was equal in power to a common
.,zed knitting needle "a centmetres in length
completely saturated with magnetism.
Neither Professor Lawrence MOI Mr.. Gage is
quite prepared to tell the reason or TINS strange
phenomenon That it is due TO the presence
Of some form of magnetic or magnetic iron ore
they have no doubt. Why it should appear IN
some and not in other bricks they are not ready
10 say Mr. Cages theory is that the methoo
AZ making bricks. taken together WIN the conn
hounds in the bricks structure IS the secret OF
tbe magnetism. He thinks this because he iouho
out thai in two bricks. that when coh'a'heo
no lime possessed the greater magnetism al
though It's portion OF iron was greater IMAM thal
In the other by a small fraction.
ct rather imagine" said Mr. .ge, that In
heating the brick the iron in some cases forms
. chemical composition with other substances
vbich destroy it's magnetism. Two KINDS OF
g., DIVIDES appear in the bricks I have ex-
,od Tbev are the black oxide, or mag
r.t,te Fe3 o., and the red oxide. not so mag
,et;c Fe2 O3. Those bricks which contain the
moro black oxide or magnetic, without ime'
are the strongest .-,...
Mr.. Gage performed all sorts or experiments
18th the bricks He attempted 70 chahse INC
r.o,es but was unsuccessful lie iouhu 'hat III
80 case the poles were either in the edges