RULE. 



Use of the line of timber-measure. This 

 resembles the former ; for having 1 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 21 * 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 method is 

 to add the two together, and take half the 

 sum for the side of the square. For round 

 timber the method is to girt it round with 

 a string 1 , and to allow the fourth part for 

 the side of the 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 buy- 

 ing and selling timber. 



RULE, CoggeshaWs sliding, is chiefly 

 used for measuring the superficies and so- 

 lidity 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 four 

 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 girt-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, 5, 6, 7, 8, 9, 10, 20, 30, 

 &c. From 4 to 5 it is divided into ten 

 parts, and each tenth subdivided into 2, 

 and so on, from 5 to 6, &c. On the back 

 side 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, divid- 

 ed into 100 equal parts, and figured 10, 

 20, 30, &c. Tue back part of the sliding 

 piece is divided into inches, halves, &c. 

 and figured from 12 to 24 ; so that when 

 drawn wholly out, there may be a mea- 

 sure of two feet. 



" Use of Coggeshall's Rule for measur- 

 ing 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 18 feet, on the 

 line B, is 180 feet, the contents on the 

 line A. 3. To measure a rhombus. Sup- 

 pose the side 12 feet, and the length of a 

 perpendicular let fall from one of the ob- 

 tuse angles to the opposite side, 9 feet ; 

 set 1 on the line R, 12, the length of the 

 side on the line A : then against 9, the 

 length of the perpendicular on the line 

 B, is 108 feet, the content. 4. To mea- 

 sure a triangle. Suppose the base 7 feet, 

 and the length of the perpendicular 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 perpendicular, 

 which is 2 on the line B, is 14 on the ling 

 A, for the content of the triangle. 5. To 

 find the content of a circle, its diameter 

 being given. Suppose the diameter 3.5 

 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 cir- 

 cle in feet 6. To find the content of an 

 oval or ellipsis. Suppose the longest di- 

 ameter 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 num- 

 ber 4 on the line is C 6, the mean propor- 

 tional sought. This done, find the con- 

 tent of a circle, whose diameter is 6 feet ; 

 this,- when found, by the last article, will 

 be equal to the content of the ellipsis 

 sought. 



" Use of Coggeshall's Rule in measur- 

 ing timber." 1. To measure timber the 

 usual way. Take the length in feet, half 

 feet, and, if required, quarters ; then 

 measure half way back again ; then girt 

 the tree with a small cord or line ; double 

 this line twice very evenly, and measure 

 this fourth part of the girt or perimeter 

 in inches, halves, and quarters. The di- 

 mensions thus taken, the timber is to be 

 measured as if square, and the fourth of 

 the girt taken for the side of the square, 

 thus ; set 12 on the girt line D, to the 

 length in feet on the line C ; then against 

 the side of the square, on the girt line D, 

 taken in inches, you have, on the line C, 

 the content of the tree in feet. For an 

 instance : suppose the girt of a tree, in the 

 middle, be 60 inches, and the length 30 

 feet, to find the content, set 12 on the 

 girt-line D, and 30 feet on the line C ; 

 then against 15, one fourth of 60, on the 

 girt-line D, is 46.8 feet, the content on 

 the line C. If the length should be 9 

 inches, and the quarter of the girt 35 

 inches ; here, as the length is beneath * 



