What is really required is to make a lightning conductor of sufficient calibre to carry down the electric discharge, however great it may be, from the summit of the building into the earth, and that the earth contact should be above suspicion and thoroughly good in all seasons.
Fig. 26 shows a plain and simple design for protecting an ordinary church. The conductor in the case of churches and all other high or extensive buildings ought invariably to be made of copper rope, other metals of less conductivity, such as iron, being inadmissible, since their employment would necessitate the use of ponderous masses of metal, which would be not only unsightly, but extremely heavy, and difficult to manipulate successfully. In the accompanying engraving (fig. 27) lent by the Society for Promoting Christian Knowledge, is shown a somewhat more complex structure and the method of arranging the conductors thereon. In this case there is a conductor attached to each spire, leading to and connected with the metal-work of the roof and gutters. On the gable _c_, and the transept gables _d e_, there are fixed three conductors which unite in the centre of the roof, from which they are carried down to the gutters. The same arrangement is followed for the smaller gables _f g h_. The water-pipes and gutters being connected with the conductors, these latter are carried down the side to the earth. It need scarcely be explained how important it is that all metal ornaments on the ridges of churches, as well as other buildings, should either be connected with the general conductors or, in the case of extensive buildings, with a conductor that is carried straight to the earth, as shown in fig. 28. In the case of the finials so often found on Gothic structures, it is necessary to splice the conductor round the bottom of the finial, as shown in fig. 29. If, instead of placing terra-cotta tiles along the ridges, a cresting of fancy iron-work is fixed there, the expense of running a conductor along the ridges will be saved.
The various methods of fixing weathercocks on to the terminal rod are fully explained in another chapter. Fig. 30 shows the best arrangement for connecting the conductor to the terminal rod on a church spire. The copper rope which forms the conductor is spliced round the terminal rod at the bottom of the finial, and as an additional security round the base of the vane rod, which in this instance also serves as the terminal rod of the lightning conductor.