8z Inflrumental InflruEiions 



Hence the Line is caird \\it Line of 30 in Ofi 

 Inch: 



Thefe Lines vdiy be made Ufe of where yoxjt 

 hpve a large Piece of Ground to protraft, ht^' 

 caufe each Divifion is eqiial to' 10 Yards, 

 Feet, or Chains, &c. Thus you fee, that the 

 Meafure of 20 Chains, 60 Links, extends from 

 the Dot on 20 to the 6th Divifion in the Part 

 Decimally divided. Bur, as thefe Lines are 

 more immediately ufeful in laying down and 

 meafuring Lines for Triangles, I pafs them 

 over, with this farther Remark, That againft 

 the other three Lines are figiir-d 24, 20, ,t^, 

 denoting that one of their P^f'tk is decimklFf 

 divided .to 24,^^0, 1 6 Parts in an Inch, • * 

 f 'i^biok -Ai yd n .^ .^ -^ I ^cl jri; •: n ibulw 



ortofc.: P'llsdT R A CT 6^K 9. ^^ 



FtoJg. -'TpHESE Inftruments are of w6 

 hv-^n X Sorts: one reprefents a Semi- 

 fcircld, or half Theodolite 5 thg other, a Pa- 

 rallelogram, or long Square; '/^''--■' . * 

 Z/iThe Protraic^or reprefcnting a Semicircle, ife 

 di'^rided in tbeLimh* or Semibircle, into 180 

 equal Parts, or Degrees 5 thofe Degrees are 

 humber'd backwards and forw^ards, from' t? to 

 180,' in two Semicircles ^ the Center of T^'ifi 

 Divifions is aJittle Notch, or Hole, made iii 

 the Line paffiiig tfiro' the two Points of jiS6 

 Degrees 5 and therefore 'ti« eafy tp imagine, 

 that the two femicircular Drvifions repmeiit 



the 



