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Rh inquiry, and it was for this reason appropriately designated a "Permanent Committee." The meteorologists concerned in its inauguration were actuated by the same consideration that was present to the Section of Physics of the Academy of Sciences in Paris when the following paragraph of the instruction of 1854 was drawn up:

One knows, it is true, a very great number of examples of people being killed or of houses being set on fire; one knows, also, many and diverse instances of metals fused, of timber shattered, of stones and even of walls thrown far away, and many other analogous effects; but what is generally wanting is precise measurements relative to distance, dimensions, the position of the object—both that which is struck and that which escaped. For it is necessary to know what the lightning spares, as well as what it strikes. It is the work of all observers, but especially of officers in the navy and artillery, of engineers, of professors, inventors, and architects, to test these phenomena at the moment they are produced, and to describe them accurately for the benefit of science, as well as that of public economy. Such descriptions, when they refer to a stroke of lightning, should as much as possible point out the track of the lightning from its highest to its lowest point; also they should show, by sufficiently numerous horizontal sections, the relative positions of all objects in a circle wide enough to take in those which have been struck.

In this passage the instruction of the French Academy no doubt touches the one point which is necessary before all else to improve, if not to perfect, the practice of electrical engineering, so far as this is aimed against the destructive powers of lightning. The broad principles upon which the engineer prosecutes his work are happily such as can be referred to actual experiments carried out by the artificial apparatus of the electrician. But there still remain some incidental questions, such as the influence of surface, extent, and form in conductors, the relation of conductivity to tenacity, the area of protection, and the maximum effect of lightning, which can not be settled in this way, and which require an appeal to the larger operations of Nature. This, however, concerns opportunities which can not be arranged at will. The method of the appeal must of necessity be observational rather than experimental. It proceeds upon the lines of close watching and systematic record. Observations where the great operations of Nature are concerned are utterly worthless unless they are made with scientific insight and precision. The plan of investigation that has to be pursued is therefore to collect an exact account of all accidents that occur, and to arrange a system of organization which enables all such chance opportunities to be seized upon and improved by an immediate investigation of concomitant conditions and circumstances. This method of study also must be followed up by patient persistence for a considerable length of time, seeing that accidents from lightning occur at uncertain intervals, and that they are scattered capriciously over the greater part of the surface of the earth. It is for this reason, essentially, that a Lightning-Rod Committee needs to sit in permanence.