Telegraph Insulation, experiments made in Paris

TELEGRAPH INSULATION. - Experiments have been made in Paris with the RHUMKORFF coil to demonstrate the effect of atmospheric charges upon insulations for telegraph wires. The spark of this wonderful instrument perforates porcelain and causes it to "leak," or permit the current of the battery to escape through the insulator. It produces the same effect on "ebonite," or vulcanized rubber. Glass insulators are fractured, while earthen-ware or porcelain insulators, saturated with paraffine, are not affected, the current from the coil passing through melts the paraffine, causing it to run and fill the hole in such manner as not to permit moisture to enter; hence the insulation is preserved. London Engineering and other British journals speak of paraffine as the most perfect insulating material known. - Philadelphia Ledger.