Page:Popular Science Monthly Volume 9.djvu/403

Rh of the valley is everywhere well filled with alluvion, and the swamps west have firm bottoms throughout the valley. Below Baton Rouge, where the river tends to the southeast, the swamps on the east are boggy and not well filled with deposits, and the large spaces covered by Lakes Maurepas and Pontchartrain are left unfilled.

"If the Mississippi had been a river of clear water (instead of being sedimentary), traversing a valley not alluvial, it would probably occupy the western side of its valley like other streams flowing toward the equator; but, as it is, it levees or embanks itself to the eastward by an excess of deposits west. It hugs the bluffs on the east side, down to the last one at Baton Rouge, for the reason that it could not be forced any farther eastward; but immediately below the last bluff, the excess of deposits west crowded the river-channel eastward still farther; the general direction thence to the present mouth being southeast. The mouth of the river having now reached very deep water in the Gulf of Mexico, and having advanced a little beyond the filling up of the gulf west, and beyond the southern limit of the western highlands, the tendency is to flow westward by the Southwest Pass, which is now the largest channel, conveying about one-third of the whole river to the sea."

Glacial Phenomena.—Prof. A. R. Grote recently delivered a lecture on "The Ice Age" before the Catholic Institute of Buffalo. He first called attention to the evidences of glacial action in the limestone rock underlying the surface deposit of sand, gravel, and clay, in that region. Another evidence of glacial action is the presence of erratic blocks; these too are found in the vicinity of Buffalo. In Europe the largest of these erratic blocks have been traced to their original site. Near Zürich, in Switzerland, there is a block estimated to weigh nearly 5,000 tons. Another block, of nearly equal weight, may be seen at Neufchâtel. By comparing their grain, structure, and form, it has been ascertained that they came from the Alps, and indeed the very ledge of rock of which they were once a part has been determined. To reach their present location they must have traversed what are now bodies of water, as the Lake of Geneva. Such blocks, of all sizes, being held fast in the ice at the bottom of the glacier, act as chisels on the rock beneath, producing scratches. And, as a river accumulates piles of sticks and rubbish along its banks, so does the glacier accumulate piles of stones and clay, known as moraines. Medial moraines are found where two glacial streams unite, just as a sand-bar marks the junction of two rivers. These medial moraines are extensions of lateral moraines which are found at the sides of the glacier. Terminal moraines are found at its mouth. Over the south-western portion of the State of New York, bowlders have been found which have come from the Lake Superior region, some of them containing copper-ore. Bowlders of transportation have also been found on the summit of Mount Washington, which is more than 6,200 feet high, showing that the glacier must have at one time overtopped this summit. The direction of the scratches shows that the general course of the ice-mass was from north to south. There was a glacier of the Connecticut, the Hudson, and the Alleghany Valleys. The ice occupied the place of the water-courses, and underneath it streams flowed to the sea.

Lieutenant Cameron's Explorations.—Lieutenant Cameron has returned safely to England from his memorable journey of exploration in Central Africa. He explored the head-waters of the Congo, an immense river-system, one of the feeders of which is the Lualaba, which drains Lake Tanganyika into the Congo, and which Livingstone supposed to be a tributary of the Nile. The Congo and its tributaries constitute one of the grandest systems of internal water-communication in the world. As to the wealth of the newly-explored country, Cameron describes it as enormous. From its mineral resources and agricultural capabilities it seems destined to become one of the granaries of the world, a centre of civilization, and the scene of iron manufactures when other parts of the world have been exhausted.

Antiseptic Properties of Thymol.—The following notes of experiments made by L. Lewin to determine the antiseptic and anti-fermentative properties of thymol we translate from Gaea. This substance, thymol,