[28] The original reads "deigned not," an obvious slip.

[29] This he does by means of a network of threads ¼ inch apart. Pfeffer, Pflanzenphysiologie, ed. 1, 1. p. 142, recommends the method and gives Hales as his authority.

[30] Pflanzenphysiologie, 1865 (Fr. Trans. 1868), p. 254.

[31] He gives it as 15·8 square inches, the only instance I have come across of his use of decimals.

[32] Arbeiten, ii. p. 182.

[33] See Sachs' Pflanzenphys. 1865 (Fr. Trans. 1868), p. 257, where the above correction is applied to Hales' work.

[34] Vegetable Staticks, p. 5.

[35] Vegetable Staticks, p. 14.

[36] Vegetable Staticks, p. 41.

[37] Janse in Pringsheinis Jahrb. xviii. p. 38. The later literature is given by Dixon in Progressus Rei Bot. iii., 1909, p. 58.