Blackfoot news. (Blackfoot, Idaho) 1891-1902, 1894-05-26

unite by means oil a new ROAD ana 10
mark ont within these limits the best
line, bearing in mind three cardinal
points-economy in the working ex-
penses, security for the traffic, and the
cost OF repairs, which should be re-
dueed to the lowest degree.
To trace road a Typographical chart
is first studied in order 10 obtain the
exact positions Of the extreme points.
The ground is then gone over in order
to complete the information furnished
by the chart and TO discover other
points II necessary which would be
preferable in a technical or commercial
point of view. These might be bridges,
which could be used with advantage
and thus realizing a certain saving, or
in the ease of stream where the con
struction of bridge presented more
facilities than at the points originally
indicated, or, again, certain depressions
in the ground which would permit the
road TO pass over hill with lower
gradiant or, lastly, where populous
centers require that the proposed road
should run through them.
& careful and well considered exam
ination having been made on the main
points Of the line, sections of more or
less length are studied so as To unite
them all, finally, with more facility.
II Is impossible 10 lay down a general
and absolute rule, 10 obtain the best
tracing between any two points. The
nature OF the ground and the intelli-
gence and liability Of the operator have
a certain bearing on the end in view.
II Is only in very rare and excep-
tional eases that road can be adyan-
tageously traced in a direct line be-
tween the two points, even when they
would be separated by n short distance.
IL is generally necessary 10 deyiate in
order 10 avoid difficulties TO give the
road the best position 10 escape heavy
Filings or cuts
In general, where the points intended
20 be united by road are situated upon
HAT ground, the natural indication is
the straight line. but more frequently
the ground is iniersected by marshes,
streams or buildings, and in that case
the tracing must be modified to suit
economical considerations, convenience
and solldlty.
The Engineers Work When the
termini are separated by sinuosities
the grades Of which are greater than
those previously fixed, by valleys,
ridges, or mountains, the direction Of
the tracing is difficult 10 determine. A
simple bird s-eye view is not sufficient;
the difficulties increase with the degree
Of the roughneSs OF the country. II
{ the road has 10 cross a chain ~ noun
iains the lowest point must be deter
/ mined at the outset in order 20 dimin-
ish as much as possible the expenses Of
the cuttings
The question OF choosing the site OF
bridges Is very important; so important,
that II the river 10 be crossed is con-
siderable the direction 81 the road must
be rendered subordinate 10 the site Of
the bridges II there exists several
practical points OF passage. they must
. lie compared carefully in order 10 select
the one most suitable and conforming
TO the following conditions; Hood
nature OF the ground FOR firm foun'
dHtiun. normal direction of the current,
stability 81 the bed OF the river, and
concentration OF the waters in the same
bed II one terminus be situated ia a
valley aud the other on the slope OF 4
hill. the solution will depend in great
part on the average slope Of the ground
between the terminal points II TINS
slopc conforms IN general 20 that
10 that already & yed the tracing Is
made in Straignt line.
The old Way. In short. II the aver
age incline Is inferior to the limit fixed
several solutions are possible.
The straigh, line might be taken. but
this tracing is not much observed today
for K happens more frequently that the
points 20 be joined are separated by
secondary valleys which would have g
lie crossed with great deal of difficulty
and inconvenience. Many Of the old
roads were constructed on this system
They were projected over mountains
and valleys regardless 81 the natural
obstacles OF the route or the interest o.
the population, and as they were pushed
on boldly, they were constructed o.
the expense Of enormous trouble anc
never were they satisfactory. The am
supposed 10 be In view. the shortening
of the distance. WAS far from being at
tanned, as the delays arising from tht
up-and -down-hill nature of the roae
heightened in reality the distance muci
more than the curves of level road
Another system consists in following
in a horizontal line as much as posslol'
tho ridge in its length, and DESCENDING
10 the second point by gradual lncllhe
This method was much employed form
eriy, ana hau Ntle uuNauAak = VI - S'''r
the streams almost at their source, ne
cessitating consequently but compare
lively nnimportant OUTLAWS for the cross
inp. But ridges which are general,
sinuous require very undnlatng trae
ing. and being but sparsely inhabited
tho road loses much of its Importance
The construction OF road bring
often to light springs which appear a
first sight harmless, but little by littl'
they saturate the soil and end by wash
Inc n away. In such cases drainage
must be vigorously applied so as to pre-
vent inevitable consequences.
Mode OF Construction. The create,
part OF the roads in France are macao Macao
emiged; il is only in towns that pavinl
stones are used. The layer of broker
stones composing the road is from IL T !.
as ccntimetres thick. This layer !
placed directly ON the beaten grosap, .,
In exceptional cases layer of sand in
,crvcnrs or even stones of certain
nagnitude In order to facilitate thu