George Forbes,
Popular Science Monthly
(1872)
“ Occasionally at the end of an eruption you may see at the bottom of the crater a small cone of lava, with a hole in its top, through which the steam pours with a hissing noise like a wave breaking on a pebbly beach, or like a blast-furnace, or, as Pliny has it, like the grinding of a saw; the intensity of the sound varying with your position. These small cones are the fumerolles; they are a foot or two high ”
George Forbes,
Popular Science Monthly
(1872)
“ After having made careful observations on atmospheric electricity for about a quarter of a century in a country where meteorological changes are more regular and less capricious than in our own island, there is no one whose deductions are more deserving of our attention; the more so as he considers that he has combined his researches into a definite law. His first fact is this: If within a distance of about fifty miles there is no shower of rain, hail, or snow, the electricity is always positive. ”
George Forbes,
Popular Science Monthly
(1872)
“ But of the variations in intensity of positive or negative electricity nothing has been said. Besides the fixed instruments at the Observatory, others are used on the mountain. Gases are collected from cracks in the earth's crust, tubes being let down into them, and the gas sucked up by a kind of bellows, to be examined at leisure. A portable spectroscope is also used during eruptions, and there is a larger one by Hoffman in the Observatory. ”
