Page:Popular Science Monthly Volume 7.djvu/648

630 points far distant and belonging to another zone. This appears most distinctly in the storms which accompany electrical displays. The peculiar intermediate position which the weather curve takes between the curves of sun-spots and temperature may possibly find its explanation in this fact. Observations recently published in Saxony confirm these conclusions in a striking manner.

Volcanic Outbreaks in Iceland.—Since the beginning of the present year volcanic action has been almost incessant in Iceland. The following particulars of the outbreaks we find in Nature: In March the Dyngjufjöll was incessantly vomiting fire, and the eruption was steadily spreading over the wilderness. The farmers in the region around the My-vatn Mountains were obliged to remove in order to find pasture for their stock, the country being covered with ashes. Early in April a new eruption had broken out in a southeasterly direction from Barfell. A party went out from Laxardal to explore, and on approaching the place of eruption they found the fire rising up from three lava-craters. At a distance of 100 to 150 yards to the west from the craters a large fissure had formed itself as the fire broke out, and the land had sunk in to the depth of about 18 feet. Into the hollow thus formed the lava had poured at first, but now it flowed in a southwest direction from the two southern craters. The northernmost crater had the appearance of being oblong, about 600 yards in length, and from this crater the molten red-hot lava was thrown about 200 or 300 feet into the air in one compact column. The top of this column then assumed a palmated appearance, and the lava fell down in small particles, like drops from a jet of water, which, as they became separated from the column, grew gradually darker, and split into many pieces, bursting into lesser and lesser fragments as they cooled. No flames were observed, but the glare proceeded from these columns and the seething lava in the craters. At times the explorers could count twenty to thirty of these columns. No real smoke accompanied the eruption, but a bluish stream, which expanded and whitened in color as it rose to a greater distance from the crater; and such seemed to be the power of this blue jet of steam that it rose straight into the air for many thousand feet, despite a heavy wind blowing.

How we keep our Mouths shut.—Bonders asserts that the mouth is kept closed, not by the action of the muscles connected with the lower jaw, but by atmospheric pressure. He has investigated this phenomenon experimentally. By employing a manometer, communicating with the space between the tongue and the hard palate, he finds, when the mouth is kept shut, a negative pressure corresponding to from two to four millimetres of the mercurial column. There are two suctorial spaces in the mouth: the principal one is bounded by the tongue below, the hard palate above, and the soft palate behind; the other is situated between the tongue and the floor of the mouth. The former is used in sucking liquid through a straw; the latter (sometimes) in smoking. Both are employed when we endeavor, with the mouth closed, to extract a foreign body from between the teeth. The mouth may be shut during sleep, when the muscles of mastication are relaxed. If a man fall asleep in the sitting posture with his mouth open, his jaw drops; the tongue not being in contact with the hard palate, the suctorial space is obliterated; the soft palate no longer adheres to the root of the tongue; and, if respiration be carried on through the mouth, the muscular curtain begins to vibrate, and snoring is the result.

Allaskan and Alëutian Mummies.—The custom of preserving or mummifying the bodies of the dead, as formerly practised by the natives of the islands in Behring Sea, is accounted for very ingeniously by Mr. William H. Ball, in the American Naturalist. On the main-land, either on the Asiatic or the American side, the custom does not appear ever to have existed. In the Chukchee Peninsula, on the Asiatic side, there is no soil in which to bury the dead, and cremation is impossible from the want of wood; hence the natives expose their dead to the tender mercies of bears, dogs, and foxes. In the Yukon Valley, Alaska, the soil is frozen hard, and excavation is extremely difficult; but timber abounds,