The Worcester spy., 1898-11-19

the natural law that governs the
chahge IN the declination of the needle
and when this is done the experts will
be able to figure back and tell inst
Where the compass pointed at any stage
Vi the history of the country BY this
means all disputes arising from the
changed direction of boundary lines will
be adjusted.
one Of the first things that has to
ne determined by the eXperimenter
Wnen he starts in at new station is
q true north and south line-the meri-
dlan Of the place at which he is oper-
atllg. Some years ago the meridian
oL worcester was determined very ac-
cuEately at the Tech, and stone pillars
WIN nnely marked tablets Of brass on
top of them were erected on the IN
sutute grounds, showing the location
eli an exactly north and south line of
several hundred feet in length. This
was done before the Introduction of the
e4ecLrlc cars on BOynton street, and was
accomplished by the compass method
NOW, however, the existence of the
heaVlIy charged trolley line on Boyn-
ton street near the stone posts marking
the line, makes it impossible to revise
'he location of the line with any de-
gree OF accuracy because the subtle
current SO affects the compass as to
make 1t entirely unreliable.
For this reason, it will be necessary
Tor Mr.. Smith to lay out a new line far
enough away from the trolley to avoid
sucn disturbance. The effect of the
trolley current is not felt when it is
more than about a thousand feet from
lhe instruments of the degree of deli
cacy that Mr.. Smith will use, so he will
go out in the direction of the boulevard
slue OF the park away from Consoli-
| dated influences to perform mis- work.
IN addition to this, the experiments
TO determine the declination will be
! earned on in conjunction with others,
70 secure certain data regarding the
Intensity of the magnetic force here
III w worcester, the horizontal component
OF the force, and many other things
that the lay observer would never
know existed unless he was told
speaking of the influence of the troll
ley Wire on delicate Instruments, the
polytechnic Institute has had an expe-
rlence with that sort of thing that has
cost 1t much good money. Before the
cars were put along Boynton street, a
magnetic laboratory was built on the
campus about 70 yards from where the
cars now run. The building was es-
pecially constructed with no iron or
~ AeN' AAAcNtupI ~ l1AdL there
might be constant magnetic field as
nearly as possible.
The building cost several thousand
collars. and was a very valuable addi-
tion to the Institute, as it was fitted
up with some very exact apparatus.
When the electric cars came, however
It's usefulness was very largely i'm
paired, for whenever a car was started
anywhere in the city, the effect Of the
current changes was such that the ex-
pertinent that happened to be going on
at the time was spoiled. Now the
builiing is of no value for the carrying
on of delicate experiments, and is not
used fraction as much as it would
otherwise be.
The coast survey has prepared a
chart from the experiments that have
already been made under its direction,
showing just what is the declination
of the compass at various points, to-
gether with the rate of change The
results of the work in Worcester will
simply give another point on this chart
When enough experiments have been
made, the officials hope to be able to
deduce the general law that governs
the change. This is a very difficult
thing to do, and the work is yet far
from a satisfactory conclusion. The
experts have discovered a general for
mula that seems to apply to the calcu-
latiOns they want to make, but they
find that to make it apply to all cases,
the insertion of certain constant guam
titles is necessary. But the constants
seem to be behaving in a refractory
manner, and it may be long before they
are finally Strengthened out
During the work here, Mr. Smith will
be assisted, as has been said by DIR.
MendenhaA and by Professor Rhoades
of the physics department of the Tech.
Much of the observing will have to be
done at night by the aid of the stars
Mr.. Smith has been for many years
an official Of the survey having bean
appointed in 1870. He was for q long
time in charge of the longitude work
of the survey, and has always been
engaged in the astronomical depart
ments. He was a member of one of
the parties that went to Chatham Is
land in 1874 to observe the transit of
Venus and has been employed in other
difficult and arduous portions of the
surveys work. He was an assistant TO
Dr. Mendenhan for q number of
months when the latter was the head
of the survey, He was educated at the
College of the City of New York, be-
ing in the class of 1871 He resides
when not away on work similar to this
with his family in Washington.