The Houston daily post. [volume] (Houston, Tex.) 1886-1903, 1899-12-10

far from complete that many more years
must elapse before the last sheet Is com
pleted. {FEtI
1t required forty three years to finish a
map of France by the Cassinis. when IS
hardly comparable to what the geoiogic
atlas of the United States, for when the
Topographic maps arc basis WIZ We
when 1t is done. The british soNorhn'hs'
for It's great ordnance map OF England
Wales and Scotland required even a long
err time. Both countries might be hiaueu
away within the boundary lines OF same
of the States, but work is performed horo
rapidly In this country.
The geologis atlas OF tho United States Is
the final form of publication TO topo-
leraphic and geologic maps ana tne pasle
for geographic maps. lhder the p'"n
adopted the entire area Oh the country 40
ldivided into small quadrangular dlstrlcts
called auadranges, bounded by certain
meridans and parallels. each quadrangle
IhelnR DESIGNATED by the name OF a primer
nal town or some permanent nolufhl iu"t-
ure within it, The map Is publishad Ia
atlas sheets corresponding to the quau
ranglos each sheet covering one-s'%teenth'
one fourth or the whole OF a geographic
degree according as the scale Is one, Two
or four miles to the inch, the scale varying
with the character of tse country, Each
sheet is seventeen and half inches IN
height and from eleven and half 10 SIN
teen inches wide, the latter varying WIN
the latitude.
Upon the sheet every road, trail and
path every stream in all It's cufVipgs'
every mountain, hill and elevation. every
city town and village, are shown win
n minuieness OF detail not possible save
in work Of such magnitude. The surface
elevations are shown by S'own contour
lines and numbers; water features ere
shown In blue. and cities. towns rail-
roads roads. etc, are indicated by APP
proprlate signs In black. Astronomical
knowledge. mathematics of high order
skill and photography and an unusua
amount OF physical endurance must be
} among the composite attainments of the
surveyors the United states geological eur
vey sends into the field every year Il
complete perhaps less than 100 sheets,
The art OF mspmakng 10 so old that II
origin is lost In n mist, IT is sort OF In
stinctive art. so 10 speak. since peopl
r semi barbsrous have been known to dra'
excellent maps for the instruction of ex
plorers. In the long history OF the de
o Yelopment Of the art OF makmaping a.
E epoch is reached in the early part Of tn
: Nineteenth century. when the system g
y curves OF equal elevation or contours, q
70 they are generally called. was introduced
: The system is the most valuable ever oe
~ VtBe1 fDf eApFshhinE tnt isi''i " -
T? topography, and without II II Is barrel
possible the great map OF the unite
States would not have been attempted
=. Certainly II would not have been possipl
| TO make II what is admitted by all author
| ities to be the most remarkable work
the kind In the world. The contour sys
TEN conceiyes the representation o.
new shore line on the sipposition ina
water has risen on the hillsides a give
Ijnterval. Assuming an interval OF TWEEN
ty feet. a hill OF 100 feet in height woul
= be deIineated by fine contours. Where tn
T. slope of The hillside as graduated the con
, tours would be comparatively far apar
and where Il Is steep they would be clio:
IN together, Remembering this, the heigi
ut Of hills and mountains, the general natul
A. OF their decliyities and indeed the who
general and detailed conhguration OF
OF given section can be studied out with
es little effort,
I'd Since the ~ the last century a
the great nniiors Of Europe have bee
Aa busy with mapmaking. A few lag benin
IT, but as TO the majority the results q
lis wonderful works The minuteness Of d
.ct tail aimed at in the preliminary surye
re may be Indicated in the one instance
90 Scotland. a comparatively small countr