546 Improv ed Method of making Roads. ‘ 
eee fhould follow the workmen, and 
fhould replace the {plinters of the large 
ftones in the holes that are made by their 
being broken, and dhould-fill the crevices 
with gravel—a {mali quantity ef gravel 
may fe fpread over the road, which will 
foon find its way into any hollow that 
may have been left in the preceding 
operations. 
One caution muft be ftviétly adliered: 
to; ftones of different hardnefs mutt not 
be mixed—they may be uled feparately, 
but if. they are ufed together, the hard 
tones will foon wear 
and the road will be unfit for repair, 
till the materials are picked up and 
forted. “There may, at firit view, appear 
but little difference betwee this and 
the common method of. making roads 
with ftone; but when the principle 
upon which thefe directions have aa 
founded, are explained, a-confiderable 
difference, in labour and expence, will 
be difcovered. | 
Two methods of breaking ftones. for 
reads, are generally practifed; they are 
either laid upon the road and broken 
with long hammers, or th ey are broken 
iz heaps by the fide of the road, and 
then Hoes upon the furface ; in both 
cafes, the ftone at which the man ftrikes 
is hable to flip from the hammer, fo that 
fometimes five or fix attempts are necef- 
fary to break one ftone ; but, when the 
ftones that are to be rote are cemented 
together by fmaller ftones, clay, and 
gravel, every biow that they receive 
upon Spe projecting furtace, telis, and 
fplits them frequently in perpendicular 
layers, through their whole depth. 
When eravel falls between thefe 
jayers, it binds them together more 
folidly "than can be well conceived with- 
ent experiment. .On the. contrary, 
when loofe ftones are thrown upon a 
road, they are Fh peried by horfes’ feet, 
-and pufhed on either fide by the wheels 
of carriages, as every perfon muft hav 
perceived who has attended to the {ub- 
ject. Another principle muft. alfo . be 
_confidered—if the rubftratum is not pre- 
vioully rendered equally hard and even, 
wherever one place is fofter than another, 
thar {pot will fubSde, and inequalities, 
that are at firft imperceptible, will, 1 
time, grow deeper; water will lodge in 
- 
break 
through the iofter, 
them, and the defcent of wheels will 
wear them deeper and deeper, rill they 
into ruts and holes; _ befides, 
where loofe ftones, broken as fmall as 
they cught to be in the common mode 
of wie: ing roads, are thrown toget her, 
they muft be laid to a great depth, or 
they will fcatter in fuch a ers as to 
be ufelefs; but, if they are managed in 
the manner thar has been already de- 
{cribed, feveri or eight inches will be 
fufficient. 
Another caution ue be obferved in 
mending an cld road: wherever a hole 
is to be filled, the edges of the hole” 
fhould be cue pe rpendicular ; and rhe- 
form or the hole thouid be changed, from _ 
that of a bow! to the fhape of a trough, 
whofe fides rife at right-angles from the — 
oe for, if fmall ftonies are. thrown 
into. a bowl, any .prefure will force~ 
a over its fides; but, in a trough 
they wil be confined, and every preffure 
will comprefs and grind them, by de~— 
grees, to a tmooth and folid furface.. 
When any ftone appears above the fur,’ 
face, it fhould immediately be broken, - 
elfe, befides the obftruétion which it op- 
pofes to carriages, it becomes an emi- 
nence, from which the whole weight that 
it fufains mutt fall upon the road below 
it; repeated ftrokes, of fuch momentum, 
foon form a hole round even a {mall 
tone, and the fucceffion af fuch holes 
foon deftroys the road. 
Where roads are made chtivel oF 
gravel, after the foundation has biea 
properly conftruéted, the gravel fhould 
be fkreened or feparated into two or 
three forts: a layer of the fineft fort, 
about two inches deep, fhould be fir& 
laid on; over this the fecond fort; then 
the coarfeft; and, by. fucceffive ‘ayers 
in the fame ander. the foundation: fhould 
be covered to the depth that is neceflary 
to fuftain the wear to which the road is 
fubjeét : but in all cafes, where there is 
a good opeee tens it is better to fupply 
the road from time to time with frefh 
materials, than to bury at the bottom 
fuch as might be ufeful at the furface.— 
I fhall defer what I have to fay upon the 
conftruétion of carriages, to another 
opportunity: as road-making is heavy 
work, and ought not to load your ufeful 
and entertaining Miicellany. _ 
R.L. Ee 

