Original Letters of Dr. Franklin. 35 
ot 
vight angle at H_ will necessarily describe the semi- -cirele, 
and the point m will describe the curve of signs. In this 
way a circle is described by a square. 
Hence by. means of a Square Rule, without slits or r pins, 
may an angle be trisected. Suppose EG (figure 4,) with a 
perpendicular part at H to be such a rule, the legs HE and 
HF being made of sufficient length. _ On the outward face 
of the rule EG mark the angular point formed by the out- 
ward face of the perpendicular part ; and on the same 
face mark any distance from the angular point, (as Hm,) 
whichis to:be the radius of the semi-circle. With this in- 
strument in the hand, supposing the angle ACB (figure 3) 
to be the angle to be triseeted and the semi-circle drawn, of 
which Hm is equal to the radius,—bring the point m to the 
side AC, and move it up or down on the said side of the an- 
gle until the faces of the square touch, at the same time, the 
extremities of the diameter, E-and FF... Then mark on the 
plane the angular point H, which will necessarily be in the 
circumference, and:knowing which the:angle may be trisect- 
edss: The: proof is:the same, as us been given in eplorehike 
torfigure 3.0) : 
oo (Phe: rule: may be aes of an entire piece ob tial or 
oe ei asfigure. 9.. Let Hm in this rule be the radius of the 
semi-circle: in figure 3. , In any: given angle, as ACB; there 
iscbutcone position of the square rule, in which its pomt m 
shall touch the side Af’, and the faces of the square, HP 
and HR,:shall atthe same time touch the extremities of the 
diameter, E and’ 5, and this position gives the point Hi in 
‘the: penis ingles oAnid thus Fishesisty other Aue (Ua Oat Jens 
Ai 
hd 
Hl sacet b, H MISCE LLANEOUS. 
basen XXI Sug peel Tieaione of Dr. naan aii anid abaners 
addressed to the late Rev. Jared Eliot ee Kallingworth, 
Came er 
2, Bau Remarks i ale Biitor. 
The late Rew: Me. Eliot was higchiye diatiheuished (forth ite 
period in which he lived) by a knowledge Sof natural sci- 
gee and by the aera abplicania which he aie oe its 
Vora Vz..aNo. 2. 20 - 
