1of this Line I ſix a Nail in the Ground, from
which I raiſe, and let fall Perpendiculars, ac
cording to the Method of the Geometers; and
to theſe two Lines I reduce every Thing
that I have Occaſion to meaſure; which ſuc
ceeds perſectly well in all Reſpects; for the
Parallel Lines are obvious; you ſee exactly
where to make your Angles correſpondent,
and to diſpoſe every Part conſiſtently, and
agreeably, with the others. But if it ſo hap
pens, that any old Buildings obſtruct your
Sight from diſcovering and fixing upon the
exact Seat of every Angle; your Buſineſs
then is to draw Lines, at equal Diſtances, in
thoſe Places which are clear and free; then
having marked the Point of Interſection, by
the Aſſiſtance of the Diameter and Gnomon,
and by drawing other Lines at equal Diſtances,
fitted to the Square, we may compleatly effect
our Purpoſe: And it will be of no ſmall Con
venience to terminate the Ray of Sight with a
Line in thoſe Places which lie higher than the
reſt; whence letting fall a Perpendicular, we
may find the right Direction and Production of
our Lines. Having marked out the Lines
and Angles of our Trenches, we ought to
have, if poſſible, as ſharp and clear a Sight as
a certain Spaniard in our Days was fabulouſly
ſaid to have, who they tell us, could ſee the
loweſt Veins of Water that run under Ground,
as plainly as if they were above Ground. So
the many Things happen under the Surface of
Earth, which we know nothing of, as makes it
unſafe to truſt the Weight and Expence of a
Building to it. And, certainly, as in all the
reſt of the Structure, ſo eſpecially in the Foun
dations, we ought to neglect no Precaution
which it becomes an accurate and diligent
Architect to take; for an Error in any other
Part does leſs Miſchief, and is more eaſily re
medied, or better borne, than in the Founda
tion; in which, a Miſtake is inexcuſable. But
the Ancicnts uſed to ſay, dig on, and good
Fortune attend you, till you find a ſolid Bot
tom; for the Earth has ſeveral Strata, and
thoſe of different Natures; ſome ſandy, others
gravelly, ſome ſtony, and the like; under
which, at certain Depths, is a hard, firm
Bank, fit to ſupport the heavieſt Structure.
This alſo is various, and hardly like any thing of
its own kind in any Particular; in ſome Places
it is exceſſively hard, and ſcarce penetrable with
Iron; in others, fatter and ſofter; in ſome
Places blacker, in others whiter; which laſt
is reckoned the weakeſt of all; in ſome Places
chalky, in others, ſtony; in others, a Kind
of Potters Clay mixed with Gravel; of all
which, no other certain Judgment can be
made, but that the beſt is reckoned to be that
which is hardeſt to the Pick-axe, and which
when wetted does not diſſolve. And for this
Reaſon, none is thought firmer and ſtronger,
or more durable, than that which ſerves as a
Bottom to any Springs of Water in the Bowels
of the Earth. But it is my Opinion, that the
beſt Way is to take Counſel with diſereet and
experienced Men of the Country, and with
the neighbouring Architects; who, both from
the Example of old Structures, and from their
daily Practice in actual Building, muſt be the
beſt Judges of the Nature of the Soil, and
what Weight it is able to bear. There are
alſo Methods of proving the Firmneſs of the
Soil. If you roll any great Weight along the
Ground, or let it fall down from any Heighth,
and it does not make the Earth ſhake, nor
ſtir the Water ſet there on Purpoſe in a Baſon;
you may ſafely promiſe yourſelf a good, ſound
Foundation in that Place. But in ſome Coun
tries there is no ſolid Bottom to be found any
where; as near the Adriatic, and about Ve
nice, where, generally, there is nothing to be
met with but a looſe, ſoft Mud.
which I raiſe, and let fall Perpendiculars, ac
cording to the Method of the Geometers; and
to theſe two Lines I reduce every Thing
that I have Occaſion to meaſure; which ſuc
ceeds perſectly well in all Reſpects; for the
Parallel Lines are obvious; you ſee exactly
where to make your Angles correſpondent,
and to diſpoſe every Part conſiſtently, and
agreeably, with the others. But if it ſo hap
pens, that any old Buildings obſtruct your
Sight from diſcovering and fixing upon the
exact Seat of every Angle; your Buſineſs
then is to draw Lines, at equal Diſtances, in
thoſe Places which are clear and free; then
having marked the Point of Interſection, by
the Aſſiſtance of the Diameter and Gnomon,
and by drawing other Lines at equal Diſtances,
fitted to the Square, we may compleatly effect
our Purpoſe: And it will be of no ſmall Con
venience to terminate the Ray of Sight with a
Line in thoſe Places which lie higher than the
reſt; whence letting fall a Perpendicular, we
may find the right Direction and Production of
our Lines. Having marked out the Lines
and Angles of our Trenches, we ought to
have, if poſſible, as ſharp and clear a Sight as
a certain Spaniard in our Days was fabulouſly
ſaid to have, who they tell us, could ſee the
loweſt Veins of Water that run under Ground,
as plainly as if they were above Ground. So
the many Things happen under the Surface of
Earth, which we know nothing of, as makes it
unſafe to truſt the Weight and Expence of a
Building to it. And, certainly, as in all the
reſt of the Structure, ſo eſpecially in the Foun
dations, we ought to neglect no Precaution
which it becomes an accurate and diligent
Architect to take; for an Error in any other
Part does leſs Miſchief, and is more eaſily re
medied, or better borne, than in the Founda
tion; in which, a Miſtake is inexcuſable. But
the Ancicnts uſed to ſay, dig on, and good
Fortune attend you, till you find a ſolid Bot
tom; for the Earth has ſeveral Strata, and
thoſe of different Natures; ſome ſandy, others
gravelly, ſome ſtony, and the like; under
which, at certain Depths, is a hard, firm
Bank, fit to ſupport the heavieſt Structure.
This alſo is various, and hardly like any thing of
its own kind in any Particular; in ſome Places
it is exceſſively hard, and ſcarce penetrable with
Iron; in others, fatter and ſofter; in ſome
Places blacker, in others whiter; which laſt
is reckoned the weakeſt of all; in ſome Places
chalky, in others, ſtony; in others, a Kind
of Potters Clay mixed with Gravel; of all
which, no other certain Judgment can be
made, but that the beſt is reckoned to be that
which is hardeſt to the Pick-axe, and which
when wetted does not diſſolve. And for this
Reaſon, none is thought firmer and ſtronger,
or more durable, than that which ſerves as a
Bottom to any Springs of Water in the Bowels
of the Earth. But it is my Opinion, that the
beſt Way is to take Counſel with diſereet and
experienced Men of the Country, and with
the neighbouring Architects; who, both from
the Example of old Structures, and from their
daily Practice in actual Building, muſt be the
beſt Judges of the Nature of the Soil, and
what Weight it is able to bear. There are
alſo Methods of proving the Firmneſs of the
Soil. If you roll any great Weight along the
Ground, or let it fall down from any Heighth,
and it does not make the Earth ſhake, nor
ſtir the Water ſet there on Purpoſe in a Baſon;
you may ſafely promiſe yourſelf a good, ſound
Foundation in that Place. But in ſome Coun
tries there is no ſolid Bottom to be found any
where; as near the Adriatic, and about Ve
nice, where, generally, there is nothing to be
met with but a looſe, ſoft Mud.
CHAP. III.
That the Nature of Places is various, and therefore we ought not to truſt any
Place too haſtily, till we have firſt dug Wells, or Reſervoirs; but that in
marſhy Places, we muſt make our Foundation with Piles burnt at the Ends,
and driven in with their Heads downward with light Beetles, and many
repeated Blows, till they are driven quite into the Head.
Place too haſtily, till we have firſt dug Wells, or Reſervoirs; but that in
marſhy Places, we muſt make our Foundation with Piles burnt at the Ends,
and driven in with their Heads downward with light Beetles, and many
repeated Blows, till they are driven quite into the Head.