C 343 ] 
The description of Lines of the second 
KIND. 
L E T the right lines a t>, ac^, "be drawn on a plane, at any 
inclination the one with the other. See Plate xiy, Fig, l , 
2, 3- 
In AD, Aq_, take a a,- am, of any givenjmagnitude, and 
draw mn parallel to AD. 
On the points a, a , let two rulers ap, ap, revolve, and cut 
■ms, a<^, in n anti fo that AQ^be every- where equal to 
M N. 
Then (hall the interfe&ion P of the rulers defcrlbe lines of 
the fecond kind, or curves of the firft kind. 
Where the right-line a a, is the hrft, or tranfverfe diamO 
ter. 
The point c, bifecting the diameter a rf, is the center. 
The right-line pd, drawn parallel to aq^, is the ordinate 
to the diameter a a. 
The part ad, or cfi, of the diameter, is the abfcifs, when 
reckoned to begin from a to c, or from c to a. 
The right line fi b drawn from the center c parallel to the 
ordinate pd, and terminated in the curve, is called the fecond* 
or conjugate diameter. 
Thofe diameters to which the ordinates are perpendicular* are 
oalled the axes. 
And am is the parameter to the diameter a*. 
The 
