[131.] Operation.
[132.] Demonstration.
[133.] Remark.
[134.] Problem IV.
[135.] Problem V.
[136.] Operation.
[137.] Demonstration.
[138.] Problem VI.
[139.] Method II.
[140.] Operation.
[141.] Demonstration.
[142.] Method III.
[143.] CHAP. VI.
[144.] Prob. I.
[145.] Prob. II.
[146.] Demonstration.
[147.] Corollary.
[148.] Method II.
[149.] Operation,
[150.] Demonstration.
[151.] Remarks.
[152.] Method III.
[153.] Operation.
[154.] Demonstration.
[155.] H I: T H:: a X: a T.
[156.] Prob. III.
[157.] Operation.
[158.] Demonstration.
[159.] Prob. IV.
[160.] Method II.