"Annales de Chimie et de Physique" tome 37 page 319.) They failed both with powdered feldspar and quartz.

One tube, formed with pounded glass, was very nearly an inch long, namely .982, and had an internal diameter of .019 of an inch.

When we hear that the strongest battery in Paris was used, and that its power on a substance of such easy fusibility as glass was to form tubes so diminutive, we must feel greatly astonished at the force of a shock of lightning, which, striking the sand in several places, has formed cylinders, in one instance of at least thirty feet long, and having an internal bore, where not compressed, of full an inch and a half; and this in a material so extraordinarily refractory as quartz! The tubes, as I have already remarked, enter the sand nearly in a vertical direction.

One, however, which was less regular than the others, deviated from a right line, at the most considerable bend, to the amount of thirty-three degrees.

From this same tube, two small branches, about a foot apart, were sent off; one pointed downwards, and the other upwards.