TREATING OF CONTRIVANCE 



appearance), turn your faces towards each other, 

 standing at a large distance asunder, but so as you 

 may both see your respective objects. And let A 

 direct B to set the pole in a line with his, and that 

 at the north-end ; and B direct A to hold in a line 

 with his, and that at the south-end; so each direct- 

 ing the other by words or signes; let both alter to 

 and fro, till they have their desires at once; then 

 shall these two, and the extreams, be all four in a 

 straight line, whereby you may set as many as you 

 please. This way I have I found out by experiment, 

 and think it worthy a place amongst the mathe- 

 maticks. 



But if you cannot see the two ends, when stand- 

 ing in the middle, altho' the poles be never so high, 

 then, if it be wood or hedges, the foresaid Ian thornes 

 and candles will do the business. 



But if the obstructions be hills, walls, or houses, 

 for which you cannot see, either by lanthornes or 

 high poles, tho' standing in the centre, then work 

 by parallels thus : set off a parallel line so far, as 

 that it may run quite beyond the obstruction, on 

 the side most convenient ; then set in the parallel 

 again at convenient places ; so shall both agree, as 

 will appear when the obstruction is removed. 



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