Harrisburg telegraph. [volume] (Harrisburg, Pa.) 1879-1948, 1919-11-21
Scientific Discussions
by Garrett P. Serviss

| Here is question which leads to
some unfamiliar, though deeply inter
esting, facts about our little, globular
rotating home in space 1--WE wer,
just having an argument on the ques
tlon whether tall buildings, such as the
woolworth and Flatiron, are built alb.
solutely perpendicular to the ground or
at slanting position. Kindly answer
Two Constant Readers" -.t
The plumb-line is the builders guide
and he never departs from it's indica-
tions except in case of particular neces-
sity. and then only under cover of spe-
cial precautions. The higher his build
ing rises the more exacting becomes
the law of gravitation in demanding
verticality as the essential condition
of safety.
A structure like the Washington
Monument, or the towers of a suspen-
sion bridge, may be braced against up
setting by having their outer surfaces
slope inward on all sides. But a build
ing that is mostly hollow within, and
broad in proportion to its height, and
yet more in proportion to the thickness
of it's walls, has its supporting MEM
bers vertical, even when the height ex-
ceeds the diameter.
In some cases of steel-frame con-
struction, like that of the Woolwortn
building, the diameter of the upper por-
tion is diminished by stepping back the
walls, but their vertlcality is preserved
above as well as below. The extreme
upper part generally takes the form of
u pyramid or frcstum of n pyramid,
and in that case the outward thrust of
Its walls is counterbalanced by ties
within. ~ i,..
There are a few eccentric buildings
of the tower forms, as at Pisa, Bologna
and Saragossa, which are famous for
being inclined very decidedly from the
vertical. but in these cases the walls
all lean in the same direction, the axis
of the entire structure being inclined
The Pisa tower, built throughout of
marble. is 179 feet Iigh and SO in diam
etee, and leans more than 16 feet from
the vertical. In 1929 1t leaned Is 1-2
feet and in 1910 16 1-2 feet; yet some
have thought that the tower was pur-
posely built with a leaning axis.
What the builder finds by the aid
of plumb-line, O tree discovers for
itself, without any external aid. 1t
obeys law of growth which keeps its
axis, as nearly as possible, vertical,
whether it stands on a level, or on the
side of a steep hill. AS the bee makes
a hexagonal cell without thinking about
it, so the tree extends itself straight
away from the center of gravity. But
IL we try to make a hexagonal build
ing, or to erect a vertical wall. we are
forced. at every STEP to correct angle or
direction.
What the tree and the bee do are
examples of perfected genius which
knows facts at first hand Human
genius sometimes approaches similar
perfection. If the mind in all cases
had that kind of power, nobody would
have to study, or learn anything, for
all truths, however complex, would be
seen and known at once, simply be-
cause they were true. Example
Zerah Colburn saying, before the num-
Der could be written down, that the
cube root Of 26s,336,125 was 645, not
because he had calculated it but be-
cause mentally he saw that it was so.
Roughly speaking, the vertical axis
OF all buildings, all around the earth.
are directed to the same central point.
But this is not quite true, because the
earth is not an exact sphere and also
because 1t Is not OF uniform density
throughout. Great mountains draw the
plumb-line appreciably aside in the val.
leys around them. Masses of matter
OF extraordinary density inside the
earth, otherwise undiscoverable. like
wise deviate the plumb-line. Building,
erected in such neighborhoods have tc
stand as the plumb-line directs. al.
though by so doing they are compellst
TO lean out of the true vertical referred
to the earth's center of gravity.
There are places in the Himalayar
valleys where the plumb-line is deviatet
as much as minute of arc th,
Alps and the Caucasus It is sometime,
deviated half minute. Even in the
level regions around Moscow and II
Northern Germany the deviation in Ger
tam localities varies from 10 to II
seconds of arc. These latter deviation,
must be due to some underground at
| traction acting out of the line of m.
! earth's center. '
Their effects, though very interest
ihg' ana scientifically important. ar,
TOO Slight to be noticed by ordinary oh.
serVation. The top OF n 200 foot wal
oeviated one minute from the yertica
would only project about seven-tenth,
OF an inch beyond its foot. But N
course to those living about 1t, It wouIf
not appear to lean at all since oil ~
surroundings would be inclined in the
same manner. But If the interior OF
the earth were, extremely irregular in
density the plumb-line might deviate te
me extent of several degrees. and in
tnat case the famous visitor from
Mars (who must be getting n uttIe
weary py this tlme) might susnac,
lhe terrestrial architects of needing q