[7] The science of pure mathematics is perhaps indebted to no one in so great a degree as to George Bruce Halstead, formerly of the University of Texas, whose labors in connection with the popular exposition of the non-Euclidean geometry have been most untiring and effectual. Vide Popular Astronomy, Vol. VII and VIII, 1900, Dr. G. B. Halstead.
[8] Note.—M may be any point on the line BA indefinitely produced.
[9] Vide Non-Euclidean Geometry, p. 91.
[10] Vide Nature, Vol. XLV, 1892.
[11] Vide Monist, Vol. XVI, 1896, Mathematical Emancipations.
[12] Vide Monist, Vol. XIX, p. 402 (1909).
[13] Philosophical Review, Vol. VII (1898).
[14] Vide Foundations of Mathematics, p. 107.
[15] Vide Foundations of Mathematics, p. 42.
[16] Vide Science, Vol. VII, p. 2, No. 158, 1898.