Lightning conductors (fig. 8) are wires of iron or copper, made to project above the highest parts of buildings and carried down to the earth; they have the power of conducting the lightning down without injury to the building, for electricity (which lightning is) travels through metallic wires for any distance without disturbance or noise (as in the electric telegraph), but bad conductors are apt to be burst and rent by it if it be strong enough, creating flashes of light and reports. Lightning strikes most readily any projecting substance or point, the highest point is therefore selected for the protrusion of the upper part of conductors. In a plain or open space, trees and animals are often struck, as they form conductors (although very bad ones) to the lightning; being bad conductors, instead of allowing it to pass quietly to the earth as do the wires, they are generally destroyed by it. It has been often stated that we should select an open space in a thunder-storm, but this would render one liable to be struck, especially if there were no object near of larger dimensions, the best plan is to stand near to any trees or houses without touching them, the danger would not then be so great, the trees or buildings being taller, would be most liable to conduct the lightning to the earth. The danger of touching or leaning against a tree in a thunder-storm, arises from the person thus making himself (as it were) part of it and incurring the same risk. Thunder-storms, which would at first thought appear to be of no utility to man, are indeed of great service; it is a common saying that thunder clears the air, this is the result of feeling and experience, but chemists have demonstrated the fact that a substance called "ozone" (a peculiar state of the element oxygen) is produced by thunder-storms; this ozone possesses the wonderful power of correcting (decomposing) putrid and unwholesome gases and exhalations which might otherwise produce fever, cholera, &c., it moreover destroys the ova or germs of many animals and vegetables which might otherwise be injurious to vegetation of more importance, the slight injury which these storms inflict here and there should weigh as nothing in the balance of utility with such universal good. Thus it is that the works of God have all the stamps of goodness, and this ought to inspire us with so much thankfulness as to overcome every fear for personal safety. Were these grand phenomena of nature, (as materialists would make us believe) the result of laws depending solely upon the physical co-operation of mere matter, good would be the exception instead of the rule, and most of them would produce effects, if not injurious at least not beneficial, but such is not the case, and throughout all the wonderful operations of nature there is not one but tends to good, for God often inflicts a small injury that a great good may result; we say a small injury, but it is questionable if the injury is not