long as they were connected with the main pipes in the street. Knowing the destructive character of lightning when it passes through air, wood, brick, stone or other non-conductor, people are naturally fearful of allowing the current to run through their houses. But the lion and the lamb are not more different than are the disruptive discharge while passing through a non-conductor and the same current passing through a good conductor. The system of lightning-conductors in use in the British navy goes through the woodwork of the vessel, the conductors sunk in the side of the masts connecting with the sea through the metal bolts in the hull. After the terrible charge of electricity had fallen on the Chichester, Captain Stewart wrote: "I examined the planks about the bolts, and found all quite fair and water-tight." (These "bolts" formed the lower part of the system of conduction, passing through the bottom of the vessel and connecting with the water.) After twenty-five years' use there had not, as we learn from the _British Nautical Magazine_ for March, 1853, been a solitary instance of serious damage by lightning on ships fitted with these conductors, though many had been struck by heavy discharges. In our own navy the conductors pass from the upper part of the mast over the side of the vessel. It is not, however, to advocate making the gas-and water-pipes the main lines of conduction that I have made these citations, but to remove in some degree the dread of "having the lightning come into the house." A better conductor would be the metal covering of the roof when such material is used. When a good metallic connection is made between a metal roof and metal rain-conductors, which, in their turn, are well connected with the earth, nothing further is needed for complete protection than a rod soldered to the roof for each chimney or other projection. But as the lightning is liable to melt the plate at the point where it enters, especially if the metal be tin or zinc, it is well to solder points at the angles. Some, "to make assurance doubly sure," carry the rods over the whole distance quite to the ground in addition. All authorities consider such a system as this to be as complete a defence against lightning as possible. "If," says Harris, "a building or a ship were perfectly metallic in all its parts, no damage could possibly arise to it when struck by lightning, since the explosive action would vanish the instant the electrical agency entered the metal. In applying lightning-conductors, therefore, as a means of guarding against the destructive effects of lightning, our object should be to carry out this principle in all its generality, and bring the building or ship as nearly as possible into that state of passive electrical resistance it would have supposing the whole mass were iron throughout."