Usually above and below the horizontaltine AM, hecause the Sines fS and<y^are equal, the horizontal Amplsetudes will be equal, (Cor. 5 th.) and be-cause the Directions still bisects theAngles between the Focus and Zenith,they must be equally above and below4 5°, and such are still the Complement©f each other to po 0 .

COR. IX.

in any two Parabola’s describ’d bythe same Impetus, and with Elevationsequally above and below 45 °, theHeight of the one Will be equal to theSublimity of the other * for, becausefC Cu ~ fC + Cu — uK,

(perTheo. 7.) and uKArCu =fC+ tCu-- CK ; but fC+ 1 FK~ CK, (Cor.4th. Theo. /th.) therefore / G+ 2 FK=/ C+ 2 Cu, and Cus= FK, that is Cu,the Height of the Parabola Au theSublimity FK, of the Parabola AFm,

fcr * J I theo-