268 



TJic Country Gentleman s Maga::inc 



passes. If, instead of a circle, you would 

 have the figure of a hexagon, draw a straight 

 line with a pen from the point c to the point d 



Fig. 3. 



in the second figure, and by placing the glasses 

 as before, you will have the figure desired. 



" So likewise a pentagon may be perfectly 

 represented, by finding the fifth part of a 

 circle, and placing the glasses upon the out- 



figure of equal sides. I easily suppose that 

 a curious person, by a little practice with these 

 glasses, may make many improvements with 

 them, which perhaps I may not yet have dis- 

 covered, or have for brevity's sake omitted to 

 describe. 



'' It next follows that I explain how by these 

 glasses we may, from the figure of a circle 

 drawn upon paper, make an oval ; and also 

 by the same rule represent a long square from 

 a perfect square. To do this, open tlie 

 glasses and fix them to an exact square, place 

 them over a circle, and move them to and 

 fro till you see the representation of the oval 

 figure you like best ; and so having the glasses 

 fixed, in like manner move them over a square 

 piece of work till you find the figure you de- 

 sire of a long square. In these trials you 

 will meet with many varieties of designs. As 

 for instance — The fourth figure, although it 

 seems to contain but a confused reiDresenta- 

 tion, may be varied into above 200 different 

 representations by moving the glasses over it, 

 which are opened and fixed to an exact 

 s([uare. In a word, from the most trifling 

 designs, we may by this means produce some 

 thousands of good draughts. 



" But that the fourth figure may yet be more 

 intelligible and useful, I have drawn on every 

 side of it a scale divided into equal parts ; by 

 which means we may ascertain the just pro- 



lines of it ; and the fourth part of a circle will portion of any design we shall meet with in it. 

 likewise produce a square by means of the " I have also marked every side of the fourth 

 glasses, or by the same rule will give us any figure with a letter, as A, B, C, D, the better 



