The morning times. [volume] (Washington, D.C.) 1895-1897, 1895-10-06

$500
Bay has been completed by the Coast and
to that department of Government work.
The survey has its home in the old Butler
Building, on New Jersey avenue and B
streets, at the brow OF the hill near the
Capitol, and there are stories of ghosts that
frequent its corridors all night, told by
old-timers to worry new watehmen.
II has been in existence ninety years, and
numbers among the men who have been its
cfiefs and their leading assistants some
of the finest mathematicians In the country.
The first SUPERINTENDENT Of this bureau
was Prof. F. Il. Hassler. who came to this
country from Berne, Switzerland, upon the
invitation OF Thomas jefferson IL is told
OF him that he was very careful OF his In
struments, which in this science must be
most accurate. He had constructed pc
culiar little cart, with specially fine
springs carefully adjusted, in which to
carry his pets from place to place as re-
Quired in his work.
An economical streak came ever Congress
one day during his service. and among other
bureaus, Prof. Hassler's was investigated.
When the committee saw the item zone horse
and cart cost OF feed, ETC., $780," they
were sure OF chance for pruning, and
promptly struck it out. When Hassler saw
this lie smiled grinly and said:
But what Shall do with my babies?"
THE Government has nothing to do with
that" was the reply. You are paid a sal
airy and must pay for your ownhorset to take
your little ones out for an airing.
'.oh, it isn't that" said the old man, de-
lighted at the success of his own joke See
here are my babies" and he unrolied
number of delicate and curiously shaped In
struments to the view of the astoDished
Congressman. They must have great
care or they will not tell true. Unexplained,
and the upshot of his timely ruse was that
the appropriation for his baby carriage"
was untouched, and something was even
added to make his work more efficient.
SPENT THEIR LIVES.
popularity of the survey is that many
OF the men connected with it have spent a
lifetime in its work One OF the youngest In
point of service was the late Robert Avery,
who left 5000 to the Smithsonian insti-
tuition. He had been at the head OF a d.
vision for a quarter OF century when he
resigned few years ago. Those whose
records re really noteworthy in the matter
of time are Prof. George A. Fairfield, 4S
years; Prof. George Davidson, 90 years,
Prof Chas. A Schott. Al years: p rof. Chas.
t Iardella, 40 years: p rof. A. F. Rogers, 4S
years, and Prof. Henry L. Whiting, 81
years. 4
The work of the survey requires OF even
the subordinates, such as coniputers,
knowledge of mathematics more extensive
than is possessed by half the professors who
teach the subject in the colleges of this
country.
Something of the nature and Importance
OF the work Of The survey can be learned
from an achievement In connection with
the base, line survey This was the location
of base line and comparison OF base
line nIe9 sureneuts made near Holton, Ind,
in 1891. At that time a comparator 100
meters "a little over 100 yards)l ong was
constructed. The work required nearly
three months. In the first place sub
stantial shed closed on two ends and one
side was built the entire 100 meters
long.
Under this was constructed a sort of
double track miniature railroad with a
heavy rectangular stone pillar at each
end of its 1C0-ne,cr length These stones
are placed on a broad foundation of stone
embedded in cement. Their tops are even
with the surface of the ground ard each is
surniountedt by brass bolt. whose upper
end terminates in a carefully turDed
hemisphere. The bolt in each is firmly
embedded in the stone and projects far
enough to receive n cap which is screwed
over the hemisphere for its projection.
Upon the hemisphere is placed steel cut
off" steel tube adjusted hy q delicate
spirit level and hair-line scale. so as 10
secure an absolute perpendicular over the
the center OF the sphere and thus mark the
beginning of the line In he mea sured.
Use A MICROSCOPE
A microscope is carefully adjusted upon
a 6 10y inch pest standing 10 inches high
over the stone pillar.
By means of microscopes and these stone
pillars the ends of the line TO be measured
are fixed within millionths of a meter.
Betw cen these ends, under the shed, is run
a train, consisting of two trucks Of three
wheels each, nicely adjusted so rs 10 run
very smoothly over the track, ard bear
ing a steel bar 8 meters long, which lies
in Y shaped trough and is, in operation,
surrounded by melting ice 10 prevent varia-
ton in its length by reason of change Of
temperature.
In one side OF this bar, near the ends,
is a silver plug, upon W hich is marked very
fine lines Silver is used because it does
not rust. By careful comparison before
leaving washington the distance be-
tween these fine lines on the silver plugs
was determined to be exactly meters
The measurement was made here by the
Government standard meter while both
the standard and the bar were immersed
in melting ice. Along beside the track,
meters apart, are set 6 by posts similar
to those at the ends, each 10 inches high.
Upon these the microscopes are to be
clamped as the measurement OF the line
proceeds.
To begin the measurement, the train
bearing the steel "lce-bar" is moved to
one end of the line to be measured, which
is approximately one end of the track
and one end of the shed. There the fine
line of the silver plug OF the 'ice-bar"
is brought to coincide with line in the
steel 'cut-off" that rests upon the brass
hemisphere In the top Of the stone pillar
The coincident Of the two lines is observed
with the microscope set upon the by 8
post. nfs
AS q matter OF fact, actual coincidence
of the lines at the end of the 'ice-bar" and
the line IN the ''cut-off" is not possible nor
necessary. but the same relationis obtained
with nicety, which the merchant secures
roughly when he puts the end Of his yard
stick at the end of the goods he is measuring.
When this perfect adjustment Of the end
of the five meters laid off on the ''tce-bar"
to the end of the line to be measured under
ing the '.ice-bar" IL moved forward one
length, and the next point in the line to be
measuredis determined with equal accuracy
by a microscope set upon the second 6x6
post and the operation is repeated till the
entire 100 meters Of east-and-west line
under the.shed has been measured within
e-millionths OF meter of absolute &C.
curacy. ~
The line thus measured under the shed at
Holton, called a comparator, bears the same
relation to tapes and other means of
making long measurements of length as
the standard meter and the standard yard
kept by the Government here does to the
yard sticks used throughout the country.
1t is in effect hinge measure line of the
world. The Prussian Geodetic Institute
has projected a standard kilometer near
Potsdam. 5ds