[29] Report of the Lightning Rod Conference, p. 4.
[30] The dimensions here set forth are greater in some respects than those “recommended as a minimum” in the report of the Lightning Rod Conference, page 6. But it will be observed by those who consult the report that the minimum recommended is just the size which, in the preceding paragraph of the report, is said to have been actually melted by a flash of lightning; and, therefore, it seems not to be a very safe minimum. It will be also seen that there is some confusion in the figures given, and that they contradict one another. For the dimensions of iron rods, see the instructions adopted by the Academy of Science, Paris, May 20, 1875; Lightning Rod Conference, pp. 67-8.
[31] See letter of Mr. R. S. Newall, F. R. S., in the Times, May 30, 1879.
[32] See Nature, June 12, 1879, vol. xx., p. 146.
[33] See letter of Mr. Tomes in Nature, vol. xx., p. 145; also Lightning Rod Conference, pp. 210-15.
[34] See Anderson, Lightning Conductors, pp. 208-10.
[35] See Lightning Rod Conference, pp. 208-10; see also the note at the end of this Lecture, [p. 52].
[36] Lecture on Thunderstorms, Nature, vol. xxii., pp. 365, 437. See, also, a very interesting paper by the late Professor J. Clerk Maxwell, read before the British Association at Glasgow in 1876, and reprinted in the report of the Lightning Rod Conference, pp. 109, 110.
[37] Nature, vol. xxxi., p. 459.
[38] See further information on this interesting subject in the Report of the Lightning Rod Conference, pp. 233-5.