Compiled by the Secretaries from several Communications.

“ The latter, when picked out of the sand, are fusible before the blowpipe like the pebble of the same substance, but they are not in sufficient quantity to act as a flux on the entire sand heated in the usual manner. The sand so treated is reddened in the first instance, changes afterwards to an opaque white, and finally is very slightly agglutinated, resembling in its shades of colour and in its cohesion that which adheres to the outermost coating of the tube. ”

“ That they are of very recent date is certain from the shifting nature of the sand hillocks in which they are found, and from their inability to remain alone and unsupported by the sand without breaking. Lightning seems to be the only agent that could at once supply the heat and the force requisite to make them. In the familiar experiment of perforating a quire of paper by the Leyden battery, a mechanical effect of electricity analogous to the present is exhibited, and instances of fusion by the same instrument it is not necessary to enumerate. ”

“ The sides of the tube are about the twentieth part of an inch thick, and are very hard and rigid.
On proceeding inwards, their substance gradually loses the appearance of sand, and becomes vitreous, the whole interior being covered with a smooth glaze. This vitrified matter is whitish or limpid, containing specks of a dark olive colour and a few air blebs. It is sufficiently hard to scratch glass. ”