DOI Page / Citation link:
https://doi.org/10.11588/diglit.19574#0462
424 H E I
little fcale M in the third figure, and your queftion is folved.
Thus having taken the Height of the figure P, and fet it on
the fcale M, it gives four feet, which (hews that a figure fix
feet high, raifed thirty feet, will appear to be but four feet. The
Heights and diminutions of the reft are found by the fame ope-
ration, provided the difbnce be the fame with that of thefe. If
the diftance be changed, the procefs muft begin anew.
The figures V, X, Y, which are in the clouds in the third
figure underneath, are of the fame Height and proportion as in
the feccnd figure. They are only here added to {hew, that, though
the method be different, the effects are the fame.
What has been faid as to the Heights and diminutions of fi-
gures on the bafe line A B in the firft method, and I T in the
fecond, muft be obferved in proportion as they are funk further
behind ; and the higheft muft have the fame relation to thofe
under ground which are in the fame line as thefe at F and P have
to that at A. Thus in the fecond rule, if over-againft the left fi-
gure N there were another figure placed on a tower forty-eight
or fifty feet high, and its magnitude required, it muft be put in
the fame proportion as N has to I.
And, inafmuch as the laft N only contains two and a half of
the fix parts which I contains, this upon the tower muft only
have two and a half of the fix parts in the figure N.
What renders this rule the more valuable is, that all the pro-
portions of figures may be learned by heart; for whoever would
be at the trouble of making this meafure, where he might add
more parts, they would ferve him for ever, and he would ren-
der them fo familiar, that in a little time he would be able to
tell offhand, that if you are at thirty-five feet diftance, and the
figure fix feet or fix parts high when on the ground j another
that fhall be of the fame fize, will only appear five feet and a half,
when raifed to the Height of twelve feet; and but five, if raifed
eighteen feet; but four and a half, if twenty-four feet; but four,
if thirty ; but three, if thirty-fix ; and two and a half, if forty-
two ; and fo on by fix and fix to any number you pleafe.
To find the Height of remote figures, whereof the firft is on a
fyountain near the eye. It is a thing that gives a great deal of fa-
tisfaction to the mind, when a perfon knows what he does ; on
which account it is prefumed that the reader will be well enough
pleafed to have the following rule :
When fuch figures are to be made, determine the Height of the
firft, that is, the (pace of ground you would have it raifed ; and at
that diftance put another figure underneath, of the fame Height
as the firft ; and from the feet and head thereof draw lines to
the horizon, by which you will have the Height of the ether fi-
gure in the champaign. To explain myfelf,
The
little fcale M in the third figure, and your queftion is folved.
Thus having taken the Height of the figure P, and fet it on
the fcale M, it gives four feet, which (hews that a figure fix
feet high, raifed thirty feet, will appear to be but four feet. The
Heights and diminutions of the reft are found by the fame ope-
ration, provided the difbnce be the fame with that of thefe. If
the diftance be changed, the procefs muft begin anew.
The figures V, X, Y, which are in the clouds in the third
figure underneath, are of the fame Height and proportion as in
the feccnd figure. They are only here added to {hew, that, though
the method be different, the effects are the fame.
What has been faid as to the Heights and diminutions of fi-
gures on the bafe line A B in the firft method, and I T in the
fecond, muft be obferved in proportion as they are funk further
behind ; and the higheft muft have the fame relation to thofe
under ground which are in the fame line as thefe at F and P have
to that at A. Thus in the fecond rule, if over-againft the left fi-
gure N there were another figure placed on a tower forty-eight
or fifty feet high, and its magnitude required, it muft be put in
the fame proportion as N has to I.
And, inafmuch as the laft N only contains two and a half of
the fix parts which I contains, this upon the tower muft only
have two and a half of the fix parts in the figure N.
What renders this rule the more valuable is, that all the pro-
portions of figures may be learned by heart; for whoever would
be at the trouble of making this meafure, where he might add
more parts, they would ferve him for ever, and he would ren-
der them fo familiar, that in a little time he would be able to
tell offhand, that if you are at thirty-five feet diftance, and the
figure fix feet or fix parts high when on the ground j another
that fhall be of the fame fize, will only appear five feet and a half,
when raifed to the Height of twelve feet; and but five, if raifed
eighteen feet; but four and a half, if twenty-four feet; but four,
if thirty ; but three, if thirty-fix ; and two and a half, if forty-
two ; and fo on by fix and fix to any number you pleafe.
To find the Height of remote figures, whereof the firft is on a
fyountain near the eye. It is a thing that gives a great deal of fa-
tisfaction to the mind, when a perfon knows what he does ; on
which account it is prefumed that the reader will be well enough
pleafed to have the following rule :
When fuch figures are to be made, determine the Height of the
firft, that is, the (pace of ground you would have it raifed ; and at
that diftance put another figure underneath, of the fame Height
as the firft ; and from the feet and head thereof draw lines to
the horizon, by which you will have the Height of the ether fi-
gure in the champaign. To explain myfelf,
The