Mansel’s Aldrich, p. 103, and Prolegomena Logica, p. 221.

Elements of Logic, Book II. chap. iv. sect. 4.

Aldrich, Artis Logicæ Rudimenta, p. 104.

Examination of Sir W. Hamilton’s Philosophy, pp. 452–454.

Pure Logic, pp 76, 77.

Pure Logic, p. 65. See also the criticism of this point by De Morgan in the Athenæum, No. 1892, 30th January, 1864; p. 155.

Boole’s Laws of Thought, p. 106. Jevons’ Pure Logic, p. 69.

On the Syllogism, No. iii. p. 12. Camb. Phil. Trans. vol. x, part i.