502 Proceedings of the Royal Society of Edinburgh. [Sess. 
22. Articles “ Oughtred,” “ Parallels,” “ Pascal ” (part), “ G. Peacock,” “ Pell,” 
“ Perpetual Motion,” “ Pfaff,” “ Playfair,” “ Pliicker,” “ Poggendorf,” 
“ Poisson,” in Ency. Brit., 1885. 
23. On the Problem to construct the Minimum Circle enclosing Given 
o 
Points in a Plane. 1885. Edin. Math. Soc., vol. iii. 
24. On Certain Formulae for Repeated Differentiation. 1885. Edin. Math. 
Soc., vol. iii. 
25. On a Method for obtaining the Differential Equation to an Algebraic 
Curve. 1885. Edin. Math. Soc., vol. iii. 
26. On the Hessian. 1885. Trans. R.S.E., vol. xxxii. 
27. Address as President of Section A of the British Association at the 
Aberdeen Meeting of 1885. B.A. Reports. 
28. Articles “ Recorde,” “ Rheticus,” “ Riemann,” “ Robins,” in the Ency. 
Brit., 1886. 
29. Article “ Sturm” in the Ency. Brit., 1887. 
30. On certain Inverse Roulette Problems. 1887. Edin. Math. Soc., 
vol. v. 
31. On the Inequality mx m ~\x — 1 >m(x — 1) and its Consequences. 
1888. Edin. Math. Soc., vol. vi. 
32. An Electrical Method of reversing Deep-Sea Thermometers. 1888. 
Proc. R.S.E., vol. xv. Title only. 
33. An Elementary Discussion of the Closeness of the Approximation in 
Stirling’s Theorem. 1889. Edin. Math. Soc., vol. vii. Title only. 
34. A Demonstration of Lagrange’s Rule for the Solution of a Linear 
o o 
Differential Equation, with some Historical Remarks on Defective 
Demonstrations hitherto current. 1891. Trans. R.S.E., vol. xxxvi. 
35. A Fundamental Theorem regarding the Equivalence of Systems of 
Ordinary Linear Differential Equations and its Applications to the 
Determination of the Order and the Systematic Solution of a 
Determinate System of such Equations. 1895. Trans. R.S.E., vol. 
xxxviii. 
36. A Summary of the Theory of the Refraction of Thin approximately 
Axial Pencils through a Series of Media bounded by Spherical 
Surfaces, with Application to a Photographic Triplet, etc. 1896. 
Edin. Math. Soc., vol. xiv. 
37. On the jo-Discriminant of a Differential Equation of the First Order, 
and on Certain Points in the General Theory of Envelopes connected 
therewith. 1896. Trans. R.S.E., vol. xxxviii. 
38. Some Elementary Theorems regarding Surds. 1901. Edin. Math. Soc., 
vol. xix. 
