Van Nostrand's engineering magazine . ce water. This for the following rea-sons : After a long drought, the ter-minating plane of action (to use SirWilliam Snow Harriss term) is situatedon the upper surface of the deep waterbearing strata, the induced charge beingconsequently collected there. After aheavy rain, however, which thoroughlyimpregnates the upper strata with water,the terminating plane of action is o\ THE PROTECTION OF BUILDINGS FROM LIGHTNING. L65 raised to the surface of the ground, andthe induced charge is accordingly collect-ed there. It is evident, therefore, that aperfect arra
Van Nostrand's engineering magazine . ce water. This for the following rea-sons : After a long drought, the ter-minating plane of action (to use SirWilliam Snow Harriss term) is situatedon the upper surface of the deep waterbearing strata, the induced charge beingconsequently collected there. After aheavy rain, however, which thoroughlyimpregnates the upper strata with water,the terminating plane of action is o\ THE PROTECTION OF BUILDINGS FROM LIGHTNING. L65 raised to the surface of the ground, andthe induced charge is accordingly collect-ed there. It is evident, therefore, that aperfect arrangement should in many sit-uations provide both for surface earthsand for deep earths. In some situations,however, such as the top of a chalk hill,deep earths would be of little value;whereas in other situations surface earthswould be inefficient—in a well-pavedtown for instance, where the surfacewater is at once earned off by gutters anddrains. A deep earth connection can be effectedin the manner shown in Fig. 13, the well Fig. 13. being carried down 10 feet below waterlevel in the driest seasons. The diame-ter of the well may be fixed at 3 feet. Itshould be rendered alkaline with lime, soas to protect the iron from rust. The bottom 10 feet should have nomortar or cement in the walls, andshould be filled in with blocks of iron conductors should terminate incast-iron pipes, offering together 24square feet of outside surface. The pipeshould be galvanized to preserve it fromoxidation. The dimensions of the pipemay be, length 10 feet, diameter 1 pipe may rest on the bottom of thewell, in a vertical position. The bestway to connect the pipe with the conduct-or is to have a flange at the top (all or-dinary gas or water pipes have suchflanges), and to rivet a small cylinder tothe inside of the pipe at the upper end, thus forming a ring or annulus, intowhich the end of the conductor can beintroduced, and the space filled in withmolten zinc, the surfaces of the cond
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
