While speaking of Mount Pelée we may recall another phenomenon connected with it, which also appears to bear out the supposition that in the volcano's activity the action of steam takes a very large share. After its first outburst Mount Pelée continued to pour out lava and great quantities of vapour, as if like some gigantic cauldron it were being fed with fresh supplies of water; and there in the early March of the following year a most amazing thing took place, under the very eyes of a celebrated investigator of volcanoes, now dead, Professor Angelo Heilprin, who was remaining on the island. A great obelisk of andesite (a stone not unlike basalt) was forced up from the crater. It rose rapidly, as much as five feet a day; and it reached altogether a height of 840 feet above the crater's lip. It was calculated to be about 300 feet in diameter at its base. It continued to push itself up for some months, sometimes sinking a little, sometimes rising like a colossal piston above a steam boiler. Its greatest height was 1100 feet above the height of Mount Pelée, and therefore at a height of 5143 feet above the sea-level. [Illustration: The New Spine of Mont Pelée, showing Fissures and Vertical Grooves Photographed on March 15th, 1903. The spine was then 82 feet lower than it became ten days later.] [Illustration: The New Spine of Mont Pelée, viewed from the Basin of the Lac des Palmistes The apex, 1174 feet above the rim directly in front; the remains of Morne la Croix on the edge of the crater at the right.] A violent eruption would reduce its mass and its steeple-like pinnacle; but after its losses it generally pushed up again. Professor Heilprin at last got near enough to observe it, and the obelisk was found to be not of pumice stone, as had at first been suspected, but of the hard rock we have mentioned. It had, in fact, been comparable to a Titanic cork of rock which had closed up some vent far down in the crust of the earth, and which had at last been lifted by the steam pressure beneath it. It finally sank back into the crater, but it was replaced by a dome of rock which underwent similar changes in height, though on a smaller scale, to those of the obelisk. The dome of rock was, however, on a more massive scale even than the obelisk, and at one period of its career a spine, 100 feet in height, like a smaller obelisk, was pushed up through its middle. This dome was examined by the explorers, the Abbé Yvon and M. Beaufroy, who found that the dome was a great mass of andesite, while about it were fragments of the rock of which the obelisk had been composed. They wrote at the time:--