^{page lxvii note *} This was in a Report to the Commissioners of Northern Lights, 10th Decembe r 1834, p. 28. Edinburgh: Printed by Neill & Co., 1835.

^{page lxviii note *} Lighthouse Construction and Illumination, 1881, pp. 83–85.

^{page lxxi note *} Trans. Roy. Scot. Soc. Arts, vol. vii., 1868, pp. 540–546.

^{page lxxi note †} This modification was independently suggested by Mr Chance and by myself.

^{page lxxiii note *} I have elsewhere (in my paper “On New Forms of Lighthouse Apparatus,” Trans. Roy. Scot. Soc. Arts) expressed my extreme obligation to Mr Balfour for the invaluable aid I had obtained from the use of his ingenious instrument, without whose help I should scarcely have undertaken to protract the designs contained in my paper.