[F] "Nature," No. 22, March 31, 1870.
| For example, the native crystals of sulphur have | a : b : c = 1 : 2·340 : 1·233. |
| Crystals of gypsum have | a : b : c = 1 : 0·413 : 0·691. |
| Crystals of tin-stone have | a : b : c = 1 : 1 : 0·6724. |
| And crystals of common salt have | a : b : c = 1 : 1 : 1. |
[H] The origin of the axes is always taken as the center of the sphere of projection.
[I] "Obituary Notices from the Proceedings of the Royal Society," No. 206, 1880, to which the writer has been indebted for several biographical details.
[J] This notice is reprinted from the Proceedings of the American Academy of Arts and Sciences, vol. xviii, 1882-'83.
[K] Reprinted from the Proceedings of the American Academy of Arts and Sciences, vol. xix, 1883-'84.
[L] A. W. Hofmann, in "Nature," February 6, 1880, to whose admirable and extended biography the writer is indebted for much of the material with which this notice has been prepared.
[M] Hofmann, loc. cit.
[N] Remarks made at the dinner of the Harvard Club of Rhode Island, Newport, August 25, 1883.