[Footnote 1: According to the _Mahawanso_ "Tamba-panni," one of those names by which Ceylon was anciently called, originated in an incident connected with the invasion of Wijayo, B.C. 543, whose followers, "exhausted by sea-sickness and faint from weakness, sat down at the spot where they had landed out of the vessels, supporting themselves on the palms of their hands pressed to the ground, whence the name of Tamba-pannyo, '_copper-palmed_,' from the colour of the soil. From this circumstance that wilderness obtained the name of Tamba-panni; and from the same cause also this renowned land became celebrated under that name."--TURNOUR'S _Mahawanso_, ch. vi. p. 50. From Tamba-panni came the Greek name for Ceylon, _Taprobane_. Mr. de Alwis has corrected an error in this passage of Mr. Turnour's translation; the word in the original, which he took for _Tamba-panniyo_, or "copper-palmed," being in reality _tamba-vanna_, or "copper-coloured." Colonel Forbes questions the accuracy of this derivation, and attributes the name to the _tamana_ trees; from the abundance of which he says many villages in Ceylon, as well as a district in southern India, have been similarly called. (_Eleven Years in Ceylon_, vol. i. p. 10.) I have not succeeded in discovering what tree is designated by this name, nor does it occur in MOON'S _List of Ceylon Plants_. On the southern coast of India a river, which flows from the ghats to the sea, passing Tinnevelly, is called Tambapanni. Tambapanni, as the designation of Ceylon, occurs in the inscription on the rock of Girnar in Guzerat, deciphered by Prinsep, containing an edict by Asoka relative to the medical administration of India for the relief both of man and beast, (_Asiat. Soc. Journ. Beng._ vol. vii. p. 158.)] The transformation of gneiss into laterite in these localities has been attributed to the circumstance, that those sections of the rock which undergo transition exhibit grains of magnetic iron ore partially disseminated through them; and the phenomenon of the conversion has been explained not by recurrence to the ordinary conception of mere weathering, which is inadequate, but to the theory of catalytic action, regard being had to the peculiarity of magnetic iron when viewed in its chemical formula.[1] The oxide of iron thus produced communicates its colouring to the laterite, and in proportion as felspar and hornblende abound in the gneiss, the cabook assumes respectively a white or yellow hue. So ostensible is the series of mutations, that in ordinary excavations there is no difficulty in tracing a continuous connection without definite lines of demarcation between the soil and the laterite on the one hand, and the laterite and gneiss rock on the other.[2] [Footnote 1: From a paper read to the Royal Physical Society of Edinburgh by the Rev. J.G. Macvicar, D.D.]