6.--To this end, one or more conducting channels of copper depending upon the magnitude and extent of the building should be systematically applied to the walls; these conducting channels should consist either of double copper plates united in series one over the other, as in the method of fixing such Conductors to the masts of Her Majesty’s Ships, the plates being not less than 3¹⁄₂ inches wide, and of ¹⁄₁₆th and ¹⁄₈th of an inch in thickness, or the Conductors may with advantage be constructed of stout copper pipe not less than ³⁄₁₆ths of an inch thick, and 1¹⁄₂ to 2 inches in diameter: in either case the Conductors should be securely fixed to the walls of the building, either by braces, or copper nails, or clamps; they should terminate in solid metal rods above, projecting freely into the air, at a moderate and convenient height above the point to which they are fixed, and below they should terminate in one or two branches leading outward about a foot under the surface of the earth; if possible, they should be connected with a spring of water or other moist ground. It would be proper in certain dry situations, to lead out in several directions under the ground, old iron or other metallic chains, so as to expose a large extent of metallic contact in the surface of the earth. 7.--All the metals in the roof and other parts of the building of whatever kind, should so far as possible have metallic communication with these Alarm Conductors, and in case of any prominent elevated chimney, it would be desirable to lead a pointed conducting tube along it to the metals of the roof; all of which satisfies the conditions above specified.