It may be laid down as an absolute fact, that a well-made lightning conductor, properly placed, and kept in an efficient state, can never, under any circumstances, fail in its action. Undoubtedly it has happened that buildings to which conductors were attached have, in many instances--of which some will be enumerated in another chapter--been struck by lightning, and even damaged; but these cases, so far from going against the truth that good lightning conductors are infallible, only serve to prove it. A close investigation of all known instances where the electric force has struck buildings, nominally protected against lightning, shows most conclusively that the conductors placed on them were either inefficient, in some way or the other, or did not lead properly into moist ground--that is, had not the all-indispensable ‘earth connection.’ There is no case on record in which a really efficient lightning conductor, properly placed, and with its terminal in technically so-called ‘good earth,’ did not do its duty; and without being dogmatic on the subject, it may well be asserted can no more fail to give protection than an efficient drain-pipe can fail to carry off the water upon the roof. Although the electric force is neither a ‘current’ nor a ‘fluid,’ often as it is so described, still the analogy holds good so far as the one here given between the drain-pipe and the conductor. And the reason is clear enough. The water, in running down a hollow tube, obeys simply the law of gravity, but no less immutable than this is that which governs the movement of the electric force. As the water has no choice but to follow the channel made for it, under the guidance of experience and mathematical calculation, so has the emanation of the electric energy no option but to pursue the path which scientific investigation has shown it always to take. Men may speak of ‘erratic’ lightning; but it is certain that the course of the electric force is as subject to cosmic laws and as immutable as that of the stars.