ONE HUNDRED THOUSAND FACTS FOR THE PEOPLE. 427 



links, which are afterward reduced to 

 acres, roods, poles, etc. 



The field requisites for a land-measurer 

 are the chain just mentioned, a bundle of 

 arrows, a cross-staff and a number of sig- 

 nals. The arrows are usually ten in 

 number and two feet in length, each has 

 a piece of red cloth affixed to the head, 

 by which it is easily distinguishable at a 

 considerable distance when stuck in the 

 ground. The use of the [arrows is to in- 

 dicate the number of chains in any line 

 of the survey. The cross-staff is a pole 

 10 links long, shod at one end with iron 

 and pointed, that it may be thrust into 

 the earth as occasion requires. A small 

 block of wood, about 6 inches square, 

 having grooves cut round its margin at 

 right angles to each other, is fitted on the 

 pole, and slides up and down, according 

 to the height of the eye ; its use is for ob- 

 taining a perpendicular from the base 

 line of any triangle to the angular point. 

 The signals are more or less numerous, 

 according to the extent of the field or 

 tract to be surveyed ; their use is to mark 

 definitely the various points and bearings ; 

 they are usually slight poles, from six to 

 eight feet in length, with a small, red 

 flag attached to each. 



Land measuring is divided into three 

 distinct operations — first, the actual meas- 

 urements in the field ; second, the plot- 

 ting or laying down on paper all the lines 

 and angles of the field, according to a 

 scale fixed on ; third, the reducing the 

 measurements of the various triangles, 

 and thence obtaining the total .superficial 

 contents ofthe whole survey. 



We shall take each division in order — 



1. The land-measurer requires an as- 

 sistant in the field, who is called the 

 leader, as it is his business to lead or 

 carry out the chain under the direction 

 of the surveyor, who, for the sake of dis- 

 tinction, is named the follower. The 

 leader is first directed to fix the signals at 

 the angular points of the field; he then 

 takes the end of the chain in one hand, 

 and the ring of arrows and the cross-staff 

 in the other, and proceeds in the meas- 

 urement of the longest or base line, under 

 the guidance of the follower, who holds 

 the other end of the chain, and has his 

 field-book ready to note down the various 

 measurements taken. The leader fixes 

 an arrow when he has extended the chain 



to its full length, and proceeds onward 

 till the follower reaches this arrow, when 

 the chain is again drawn tight, the leader 

 leaving another arrow, and the follower 

 taking up the one first left. The entire 

 line is thus passed over, the leader leav- 

 ing his arrows as the chain runs out, and 

 the follower gathering them up as the 

 data of the measurement. The follower 

 must be careful to observe that the leader 

 keeps in the line between him and the 

 signal toward which they are measuring; 

 and he must also direct him to give in- 

 formation when he arrives at any point 

 on the line whence a perpendicular may 

 be raised to the angles on either side. 

 When the leader intimates his arrival at 

 any such point, both he and the follower 

 stop, draw the chain tight and leave it 

 extended on the ground. The follower 

 does not remove the last arrow for the 

 present, but leaves it standing and lays 

 those he has gathered up beside it ; he 

 then proceeds to the place where the 

 leader has stopped, and, taking the cross- 

 staff, ascertains the precise point whence the 

 perpendicular can be raised to the angle. 

 This is done in a very simple manner — 

 the cross-staff is planted close to the 

 chain, and one of the grooves made to 

 coincide with it; or, in other words, on 

 looking through the groove in opposite 

 directions, the measurer must see the 

 point whence he set out, and the point 

 to which he is tending; then looking 

 along one of the grooves at right angles 

 (without disturbing the position of the 

 cross-staft), he must see whether it bears 

 directly on the angular point; if it do 

 not, the cross-staff must be moved back- 

 ward or forward along the chain till the 

 precise point is determined ; its position 

 on the line of measurement is then noted 

 on the field-book, an arrow is planted at 

 the spot, and the leader and follower, 

 taking their respective places, proceed 

 with the measurement of the remainder 

 of the line; which having completed, the 

 various perpendiculars are measured from 

 the points indicated by the arrows. 



If the subject of the survey be a tri- 

 angular or quadrilateral field, with straight 

 sides, the field work is completed when 

 the longest line (that is, the base in the 

 triangle and the diagonal in the quadri- 

 lateral) and the perpendiculars are meas- 

 ured. If the field is contained under a 



