SCIENCE.

Patea Mail, Volume II, Issue 191, 7 February 1877, Page 2

SCIENCE.

Tiif, question why there arc no forests on the prairies is one which must often have occurred to travellers on our great western plains. An answer is suggested by Professor J. I). Whitney in the American Naturalist. The prairies consist largely of silicious and clayey deposits of almost impalpable fineness. This fine material, according to Professor Whitney, is especially inimical to the growth of trees. In the hilly regions of the cast it has been washed away by streams whose fall gives sufficient velocity for that purpose ; but on the comparatively level prairie areas there are no such rapidly flowing streams, and hence there is nothing to make the soil sufficiently coarse to favor the growth of timber. The reason that tree-growth in the West is so frequently limited to the bluffs along the rivers is, that the descent is so abrupt that the water which flows down to the stream during the rains carries off the finer material of the surface. On the lofty table-land of Central Asia, known as the Pamir Plateau, or “ Poof of the World,” eleven thousand feet above the level of the sea, is a lake named Kara-Kul, which has been the subject of earnest dispute among geographers, some of whom have given it an eastern outlet, some a western outlet, and others two outlets, one flowing in each direction. It now turns, out to have no outlet at all. A Russian scientific expedition visited the Pamir steppe last summer, and the lake was accurately surveyed by two of its members. They found the length to be about fourteen miles, the width ten, the water

clear but so latter that horses would drink it onlv when vary thirsty, yet

nevertheless containing 1 many fish. T l>e most remarkable phenomenon about this celebrated lake is that the level rises noticeably once every week, generally on Friday; at least so say the natives, and the Russian observations tended to confirm the statement.

There were several sailors in the re-cently-returned English Arctic expedition who took no anient spirits whatever (hiring their long stay in the frozen regions, and yet they were able to endure the severest labour and exposure to the most intense cold without injury. In his official report, Captain Naims speaks of the preference which the sledge parlies showed for tea over the usual mid-day allowance of spirits, saying that both men and officers were unanimous in favour of the change,“ and willingly put up with the misery of standing still in the cold with cold feet during the long halt needed for the purpose of boiling the water.” In ascci'tnimng the speed of a Vessel by means of the ordinary ship’s log, it is necessary to haul the log oil hoard after it has been in the water awhile. This necessity is dispensed with by an invention recently tested with most satisfactory results at Southampton. Mr C. E. Kclway lias devised what he calls an electric log, whereby the indications given by an ordinary log in the water are almost instantaneously transmitted to the ship’s deck, and there accurately recorded on a dial.