It is not uncommon for the fulgurite tube to divide in two or three branches, each of which gives birth to little lateral branches of 2 or 3 centimetres long, and ending in points. There are also solid fulgurites and foliated fulgurites. The former, no doubt, had a canal originally, which has been stopped up by matter in fusion. The latter, instead of being stretched out in cylindrical form, are composed of slender layers like the leaves of a book. The scientific museum at the Observatory of Juvisy possesses a very curious fulgurite which was offered to me some years ago by M. Bernard d'Attanoux, and found by him in Sahara. It is not a tube ending in a point. The lightning penetrating the sand, vitrified it on its passage, and branched irregularly in three principal directions. One might say it was slag formed by the juxtaposition, irregular and crumpled, of three blades of vitrified sand, which would be pressed together by leaving a narrow opening to their central vertical axis. This fulgurite, which is extremely light, measures six centimetres in length. It was found in the sand of Grand-Erg, at a depth of several centimetres. It has been found possible to produce miniature fulgurites by means of our electrical machines. By adding ordinary salt to the sand, and directing a strong current into it, complete vitrification of a tube of several millimetres is obtained. CHAPTER VIII THE EFFECTS OF LIGHTNING ON METALS, OBJECTS, HOUSES, ETC. When lightning strikes the earth, it makes straight for metals. Their perfect conducting powers place them in the first rank of conductors, and the innumerable cases of lightning with which they are associated have gained them a certain celebrity in the annals of thunder. We know, indeed, the preference of the spark for metals; we know it nurses a veritable passion for nails, wire, bell-pulls, that it dotes on rain-spouts, leaden pipes, and telegraph wires, that it is very feminine in its adoration of jewels, which it sublimates sometimes with a truly fantastic dexterity. Now and then lightning deviates from its path, and performs acrobatic feats, elfin capers to reach the objects it covets. On April 24, 1842, it struck the church of Brexton, springing on the cross of the steeple at first and running down the stem, but, arrived at the masonry which supported it, broke it into pieces; then with one bound it fell upon a second conductor, whose support was also broken. Finally, it struck a third conductor much lower down. The fluid often searches for metals hidden beneath non-conductors, which it breaks or pierces. It avoids the mattress to pursue the iron of the bed, glances off the windows to glide over the curtain-rods, or the lead of the sash. It has been seen to penetrate thick walls to reach the iron safes hidden behind them. We have already mentioned the case of the woman who, without having been killed, had her ear-ring split. Well, we have a certain number of similar examples to that.