RULE. 
latter is miiiibered from 7 to 36, 4 inches 
from tile other end. We shall point out 
some of the uses of this rule. 
The application of the inches, in measur- 
ing lengths, breadths, &c. is obvious. That 
of the Gunter’s line, see under the article 
Gunter’s Line. 
The use of the other side is that with 
which we are now concerned. 1. The 
breadth of any surface, as board, glass, &c. 
being given, to find how much in length 
makes a square foot. Find the number of 
inches the surface is broad, in the line of 
board measure, and right against it is the 
number of inches required. Thus, if the 
surface were eight inches broad, eighteen 
inches will be found to make a superficial 
foot. Or more readily thus : apply the rule 
to the breadth of the board, or glass, that 
end, marked 36, being equal with the edge, 
the other edge of the surface will show the 
inches, and quarters of inches, which go to 
a square foot. 2. Use of the table at the 
end of the board-measure.- If a surlace 
be one inch broad, how many inches long 
will make a superficial foot f look in the 
upper row of figures for one inch, and un- 
der it in the second row is twelve inches, 
the answer to the question. 3. Use of the 
line of timber-measure. This resembles the 
former ; for having learned how much the 
piece is square, look for that number on 
the line of the timber-measure; the space 
thence to the end of the rule is the length 
which, at that breadth, makes a foot of 
timber. Thus, if the piece be nine inches 
square, the length necessary to make a 
solid foot of timber is 2li inches. If the 
timber be small, and under nine inches 
square, seek the square in the upper rank 
of the table, and immediately under it is 
the feet and inches that make a solid foot. 
If the piece be not exactly square, but 
broader at one end than the other, the me- 
thod is to add the two together, and take half 
the sum for the side of the square. For 
round timber the mgthod is to girt it round 
with a string, and to allow the fourth part 
for the side of tlni square ; but this method 
is erroneous, for hereby you lose nearly one 
fifth of the true Solidity ; though this is the 
method at present practised in buying and 
selling timber. 
Rci.e, Coggesliall's sliding, is chiefly used 
for measuring the superficies and solidity 
of timber, &c. It consists of two rulers, 
each a foot long, one of which slides in 
a groove made along the middle of the 
other. 
On the sliding side of the rule are fouf 
lines of numbers, three whereof are dou- 
ble ; that is, are lines to two radiuses ; and 
one, a single broken line of numbers: the 
three first, marked A, B, C, are figured 
1, 2, 3, &c. to 9 ; then 1, 2, 3, &c. to 10. 
The single line, called the gift-line, and 
marked D, whose radius is equal to the 
two radiuses of any of the other lines, is 
broke for the easier measurement of tim- 
ber, and figured 4, .9, 6, 7, 8, 9, 10, 20, 30, 
&c. From 4 to 5 it is divided into ten parts, 
and each tentli subdivided into 2, and so 
on, from 5 to 6, &c. On the backside of 
the rule are, 1. A line of inch-measure, 
from 1 to 12; each inch being divided and 
subdivided. 2. A line of foot measure, 
consisting of one foot, divided into 100 
equal parts, and figured 10, 20, 30, &c. 
The back part of the sliding piece is di- 
vided into inches, halves, &c. and figured 
from 12 to 24; so that when drawn wholly 
out, there may be a measure of two feet. 
“ Use of Coggeshal’s Rule for measuring 
plane superficies.” 1. To measure a square : 
suppose, for instance, each of the sides 5 
feet ; set 1 on the line B, to 5 on the line 
A ; then against 5 on the line B is 25 feet, 
the content of the square on the line A. 
2. To measure a long square. Suppose 
the longest side 18 feet, and the shortest 
10 ; set 1 on the line B, to 10 on the line 
A ; then against 1 8 feet, on the line B, is 
180 feet, the contents on the line A. 3. 
To measure a rhombus. Suppose the side 
12 feet, and the length of a perpendicular 
let fall from one of the obtuse angles to the 
opposite side, 9 feet ; set 1 on the line B, 
12, the length of the side on the line A: 
then against 9, the length of the perpendi- 
cular on the line B, is 108 feet, the con- 
tent. 4. To measure a triangle. Suppose 
the base 7 feet, and the length of the per- 
pendicular let fall from the opposite angle 
to the base 4 feet ; set 1 on the line B, to 7 
on the line A ; then against half the perpendi- 
cular, which is 2 on the line B, is 14 on the 
line A, for the content of the triangle. 5. 
To find the content of a circle, its diameter 
being given. Suppose the diameter 3.9 
feet ; set 11 on the girt line D, to 95 on 
the line C ; then against 3.5 feet on D, is 
9.6 on C, which is the content of the circle 
in feet. 6. To find the content of an oval 
or ellipsis. Suppose the longest diameter 
9 feet, and the shortest 4. Find a mean 
proportional between the two, by setting 
the greater 9 on the girt line, to 9 on the 
line C; then against the less number 4 
