This tendency of certain localities to receive the electrical discharge is further illustrated by the number of times certain buildings in every considerable town have been struck. As before stated, the elevation of the structure does not seem to be the determining influence in directing the stroke, for the unfortunate edifice often stands much lower than some others in the vicinity which have always been struck. Numerous illustrations of this can be found in the records of European countries. Hollis Street Church in Boston has been struck several times, though the ground on which it stands is but little above the level of the sea, while the State-House, on the very apex of Beacon Hill, with great quantities of metal in surface and mass, is not known ever to have received a disruptive discharge. It has been supposed that the copper covering of the roof, including the gilded dome, its rain-pipes and four excellent lightning-rods, have had the effect of neutralizing the air about it by constant conduction of mild currents. Yet the rod on the spire of Somerset Street Church, nearby and eastward of the State-House, but lower, has been seen to receive a disruptive discharge. Bunker Hill Monument, about a mile north-west and some twenty feet higher, has several times received powerful discharges, which a good conductor has always carried harmlessly away. There has also been observed a tendency of the current not only to strike certain buildings, but to enter the earth at a certain point whenever such buildings are struck. Some of our oldest and most successful appliers of rods believe that at certain points there are natural electric currents, or at least readier conduction for them than at others. Yet these points can become known only by repeated disasters. Lightning-rod men who are adepts in their business now take care to overcome adverse currents by enlarging the lower part of the conductors and by carrying them to greater depth. Soon after the powder-magazine of the Boston Navy Yard was completed the neighboring residents grew fearful, and petitioned the authorities that it should be better protected from lightning. It had already four excellent rods, one at each corner of the building; but to these peaceful and unwarlike citizens every thunderstorm was a great battle in which their homes were in danger of destruction and their own lives in jeopardy. The result of their action was, that a trench four feet deep was dug entirely around the magazine, and in its bottom was laid a continuous line of sheet copper four inches in width: to this the plate of each rod was soldered, and then the soil was replaced.[6] No one could doubt now that the stealthy upward stroke would be caught and the mysterious earth-currents overcome. It is supposed that thenceforth the tremors of the good citizens ceased. The massive magazine with its fiery contents yet stands, though terrible peals of thunder have shaken it and fearful bolts have fallen near.