The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-01-10
MAGNETISM IN BRICKS.
Experiments Made by Prof. Law
renee at Rochester University.

Experiments Made by Prof. Law
renee at Rochester University.
From Rochester Democrat and Chronicle.
Probably the idea that a humble red
brick would ever play any part in cleo
trical experiments has occurred to few.
However, this is just what a certain lot
of bricks, composing a pier at the Rey-
nolds laboratory, did, and will continue TO
do as long as they are within reasonable
distance of the delicate electrical instru-
ments used in the laboratory A suspi-
cion that the above contingency might ex-
list has been in the mind of Prof Henry
E. Lawrence, of the University of Roch-
ester, for some time past. That it is
reality he now feels sure, and the methods
he used TO come to that conclusion are
most interesting.
The professor in collaboration with
Otis A. Gage, a special student in cleo
tricity, began a series of experiments COW
ering some months. The performance of
magnetometer which was used in meas
uring the magnetic power of a steel bar,
was the first cause for suspecting that
the bricks were other than what their APP
pearance would lead one to think. The
magnetometer had rested on brick pier
for the purpose of making it plumt. Not
long after Prof. Lawrence, while in Ann
Arbor, heard of similar experience oc-
curing there. On his return the expert
ments went on with more zeal than ever.
Bricks of all varieties were put through
any number of tests, and the great ma
jority were found to be magnetic. Those
manufactured by water power, known as
hydraulic" bricks, proved to be exceed
ingly strong, one equaling the power of
a steel needle % centimeters in length.
This same block of clay would make no
ticeable reflections in comparatively crude
instruments, while delicate ones would
fiutter percepubly.
One of the bricks, a plain white one
automatically pressed, possessed no mag
netism. A certain amount of lime enters
into the composition of white brick, such
as was used, and its presence undoubted-
ly had much TO do with the absence of
magnetic power. 1t was discovered that
the bricks gained magnetism in the pres
ence of a dynamo though the surrounding
of the bricks by wire coils made no per-
ceptible difference. Heating the bricks
served in a measure to decrease the mag
netism, though in each case a minute
amount was retained
To just what cause this is due neither
gentleman is ready to state. 1t is the pres
ent opinion, however that there is more
or less magnetic in the clay of which the
bricks are made. The mode of manufac-
turing is also thought to have something
to do, with the phenomena. As stated
above, the presence of lime served to de-
crease the magnetism, while the absence
allowed of greater power. The professor
thinks che Importance of his discovery
obvious. The slightest trace of unsuspect-
ed magnetic power in the structural part
of a laboratory is necessarily fatal to nice
ty of electrical measurements.
That CLAW when worked ever so little
by human agency, gathers magnetic pro-
critics has been thought for some time.
Eminent Italian scientists have made in
Vulnerable experiments in that line during
the past half dozen years. Their greatest
proof was found by experimenting with
several examples of ancient pottery,
which had been buried for centuries.
Crude as they were, magnetism was found
to exist in no uncertain quantities.