Conductors affixed to houses should always be pointed, and the point should be kept in a state of cleanliness, and the conductors should terminate in a moist stratum of earth, or in London it might safely be conveyed into the common sewer. It has been objected to the use of pointed conductors, that we invite the lightning to the point; and that is true to a certain extent, and in gunpowder mills the conductor should be placed at some distance from the building. The conducting rod should be of copper or iron, and from half to three-fourths of an inch in diameter, so as not to be readily forced. Its upper end should be elevated about three or four feet above the highest part of the building, and all the metallic parts of the roof should be connected with the rod, which should be continuous throughout. As regards the question of what is the safest situation in a thunder-storm, we should be pretty safe in the middle of a large room in bed; we should be pretty safe among the feathers, which are bad conductors; but as the bell-wires will conduct the electricity into the room, the bed should be removed from them. It would be well to stand at a distance from the chimney on a woollen rug, which is a non-conductor. When out of doors, I scarcely need to say, that you should never stand under a tree; the tree being moist, the electric fluid generally passes down between the bark and the substance of the tree, splitting it in all directions, and the lightning will pass to the best conductor near it; if any unfortunate animal should happen to be under the tree, it will be killed. The safest plan is to go toward the middle of the field, at a distance from any tree, and to stretch yourself out upon the ground, although this is not a very pleasant situation, especially in hard rain. During a thunder-storm, the earth is in a state of electricity as well as the clouds, and the light and heat which are produced at the explosion indicate the annihilation of the two electricities. Sometimes the discharge is only from cloud to cloud, sometimes from the earth to the clouds, and sometimes from the clouds to the earth, as one or other may be in the positive or negative state. The clouds are usually more or less electrical when the vapour, floating about in the atmosphere, is condensed, and the earth being brought into an opposite state of electricity by induction, a discharge takes place, when the clouds approach within a certain distance, and sometimes the electric cloud perches upon a hill, and then discharges itself. The electricity passes through the clouds in a zig-zag direction, and the undulation of the air which it produces is the cause of the noise which we hear, called thunder, which is more or less intense, and of longer or shorter duration, according to the quantity of air acted upon, and the distance of the place where the report is heard from the point of discharge. If the danger be great, we have seldom any