The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1891-06-04
The Merits and Dement'S OF Many
Kinds Shown by Or. a. q.
Swallow.
Interviews With Main street Property
Holders Indicate That Granite Has
the Preferences with Them.

ject much consideration. Among other
things DR.. Swallow said:
A road bed to be safe must be such that
mon and horses and vehicles can pass over
it at the usual speed and not be in danger
of sticking in the mud or of slipping and
straining their joints or of excessive joltinR.
This il a matter of no small Importance
whore the comfort and safety of hundreds
and thousands will be at stake every day.
A road bed to be economical must not
cost too much at first and must be durable.
II two contractors propose to put down
pavements at the same cost, it will be wise
and in accordance with common economy
to choose that which will last the longer,
other things being equal.
In the matter of durability of pavements,
ii is in the limits OF what is proposed for
our pavements to choose between rockz
which will not last more than ten years and
rocks which will last a hundred years.
A great many kinds of rocks have been
used in our cities for paving streets during
the last hundred years. but it will be neces
sary to refer to a few only as the first trial
showed the most of them unsuited to that
use.
Cobble pavements-Some of the earliest
pavements in our eastern cities were made
of small boulders. These pavements were
cheap and very durable, as some of them
still exist which were old a hundred years
ago But these boulder or cobble-stone
pavementS are very rough and hard on
horses and vehicles of all kinds. Helena
has enough cobble stones in the CITY limits
to pave all her streets, and they could be
put down at little cost; but cobbls pave
m0nfaQ ara t0n hard on hnrHAa and NIL kju1u
of vehicles to be satisfactory.
Flag pavements. Many rocks split easily
into broad hag-stones, which can BE-
cheaply used in paving. But the broad
surfaces wear too smooth for the safety Of
animals used in the streets, and they are
not durable in a street used for heavy
traffic. FlaRG of the best quality are found
near our city, which will make excellent
sidewalks.
Iron %pavements have been used in some
places, but for various reasons they have
not proved satisfactory.
Wood pavements have been extensively
used in many cities. 1t is very clean and
Easy on horses and carriages; but it is not
SO durable as some stone pavements.
Macadam ~pavements have been very ex-
tensively used in st. Louis and other cities,
but the rocks are ground up by use too fast
and form too much dust and mud to be
fully satisfactory. -eae- .-. 49,. w.
Asphalt pavements have been used in
some of our cities, as in Washington and
Chicago. They are clean and easy on
proved economical, I am not prepared to
say. But it is evident this pavement would
not do for Main street, with it's heavy
wagons and everlasting wear and tear. Its
nae in our sidewalks appears to be much
better than wood.
to be settled that mall blocks of some dura-
BILE rock make the best pavement for streets
having q large traffic with loaded drays and
wagons. The blocks must be small to pre-
vent the wearing from forming a smooth
and dangerous surface.
For these payements various rocks have
been used, sonic because they were most
convenient, others because contractors
could use them with greater profit, and
others still because they are most durable
n hence most economical.
Limestone block pavement has been used
Louis, because this rock WAS moro conven-
lent than any other. since that CITY is built
upon limestone and the country around it
is underlaid with them. Some limestones
are much more desirable than others; but
all of them have proved unsatisfactory.
They wear too rapidly and form very disa-
greeable dust II mud. st. Louis has had
some of the best varieties of limestone, and
after a long trial has condemned them all.
We have some good durable limestonesn ea .
our city; but it would be folly to use what
long experience has proved to be a bad ma
terlal for pavements.
Granite block pavements have been ex-
tensively used in many cities. Boston has
given it a thorough trial and st. Louis has
commenced substituting it for limestone
and wood. In some places granite has been
condemned and in other places it has
proved more satisfactory. These different
opinions are due to two or more causes.
Some GRANTEES are easily decomposed BY
the action of heat and frost and are rapidly
worn away. and crushed by heavy
wagons, while other GRANTEES are much
more durable, and have proved more
cause they are moro convenient and can be
worked cheaper than better materials.
There are a great variety of GRANTEES near
Helena-some bad. some better. In some
places GRANTEES remain popular on the
credit of other rocks which are very gene
harder. tougher and more durable than
granite. The famous Quincy GRANTEE
80 extensively used in various parts
of the country, is not a granite, but a
syenite.
Syenite block pavement has been much
than any above named. Syenite differs
from granite in having the tough. strong
hornblende instead Of the scaly, easily
crushed and decomposed mica as one of its
ingredients. We have many deposits of
syenite-some worthless, others very good
and durable.
Slate block pavemsnts have been used, as
havo sandstones, gneiss and some other
rocks, for flag and block paving. but as
stated above, all the flag pavements have
been found to wear slippery and dangerous,
or to wear out so rapidly as to be unproft-
able; though they can be quarried and laid
at so little cost. No slate, sandstone,
gniess, mica, schist or other rocks of SINH
lar structure. will do for paving under so
heavy u traffic as Main street has.
Porphyry pavements arc used will vari-
GUS results. We have some porpbyries suf-
1iciently hard and durable to make a good
pavement. and some SO soft and perishnble
AS to be worthless for such use, as it has
proved in other places.
Montana has a great variety of sgneous
rocks which would make clean, durable
tA.yements, We have trachytes, green
hsSnes. diorites, dolerites and other trap
rocks i'll numerous varieties md in great
abundance, which are the best rocks ever
used in paving streets for a heavy traffic.
Bnsalt paveInents have been used in some
of our cities, AZ i'll Broadway, Now York,
which probably has tho heaviest traffic of
any street in America. Where GRANTEES and
s~yenites wear out in a short time under the
everlasting crush of drays, buses. hacks
md cabs, basRlt has stood the wear and
tear of II century.
Greensboro pavements are quito as hard
md durable as hasalt and make quite az
good II pavement. 1t may cost II trife
moro to mako a pavement of basalt or
greensboro, for they arc harder and tougher