employed, which never could be relied upon with confidence. Enormous quantities of explosives are now used in blasting on a large scale, where many tons of hard rock have to be removed. One of the most striking blasting feats was the blowing up of Flood Island, better known as Hell Gate. This was a rocky islet, about 9 acres in extent, situated in the East River, New York. It was a continual menace to shipping, and after many fine vessels had been wrecked upon it the authorities decided that it should be removed. The rock was bored and drilled in all directions, the work taking more than a year to complete; and over 126 tons of explosives were filled into the borings. The exploding was carried out by electricity, and the mighty force generated shattered nearly 300,000 cubic yards of solid rock. CHAPTER XXVIII ELECTRO-CULTURE About thirty years ago a Swedish scientist, Professor Lemström, travelled extensively in the Polar regions, and he was greatly struck by the development of the Polar vegetation. In spite of the lack of good soil, heat, and light, he observed that this vegetation came to maturity quicker than that of regions having much more favourable climates, and that the colours of the flowers were remarkably fresh and clear, and their perfumes exceptionally strong. This was a surprising state of things, and Lemström naturally sought a clue to the mystery. He knew that peculiar electrical conditions prevailed in these high latitudes, as was shown by the wonderful displays of the Aurora Borealis, and he came to the conclusion that the development of the vegetation was due to small currents of electricity continually passing backwards and forwards between the atmosphere and the Earth. On his return to civilization Lemström at once began a series of experiments to determine the effect of electricity upon the growth of plants, and he succeeded in proving beyond all doubt that plants grown under electrical influence flourished more abundantly than those grown in the ordinary way. Lemström’s experiments have been continued by other investigators, and striking and conclusive results have been obtained.