§ 27 n. 1. Camb. Phil. Trans. Vol. X, On the Syllogism, No. IV, and on the Logic of Relations. Cf. ib. Vol. IX, p. 104; also his Formal Logic (London, 1847), p. 50. ↩

§ 27 n. 2. See especially his articles on the Algebra of Logic, American Journal of Mathematics, Vols. III and VII. The subject is treated at length by C. S. Peirce’s methods in Schröder, op. cit., Vol. III. ↩

§ 27 n. 3. See his article On the Nature of Judgment, Mind, N. S. No. 30. ↩

§ 27 n. 4. See my articles in R. d. M. Vol. VII, No. 2 and subsequent numbers. ↩

§ 30 n. 1. There is a difficulty in regard to this primitive proposition, discussed in §§ 53, 94 below. ↩