Science Notes.

Freethought Review, Volume I, Issue 5, 1 February 1884, Page 5

Science Notes.

A German inventor has recently applied the principle of hydraulic reaction to the propulsion of a boat so successfully as to awaken considerable interest. The principle is very simple, consisting of steam pumps, and tubes through which the water is admitted at one end of the ship and forced out at the other. The German navy officers are especially interested, and by experiment are testing the value of the invention. It is rather remarkable that about thirty years ago similar experiments were tried in the British navy with unsatisfactory results. During the last cholera epidemic in Egypt the German Government sent commissions to enquire into the causes and prevention of this frightful plague. One of these Dr. Koch, the celebrated biologist, who was the first to discover the “bacillus” or germ of consumption, has satisfied himself that cholera is due to a similar living microscopic organism. }The Doctor has now gone to British India to continue his researches in that country. This and other discoveries of late years bear out in a remarkable way the truth of Professor Tyndall’s germ theory. At a meeting of the Academy of Sciences on October ist, M. Faye argued that the progressive cooling of the earth’s crust goes on at a more rapid rate under water than on dry land, and therefore that the solidified crust is much thicker under theocean than on the continents. Hence he maintains that the liquid mass in the interior of the globe is subjected to far greature pressure under the seas than under the main land; and as this excess of pressure is diffused in every direction, the less dense continental crust must yield to the pressure thus exerted, while the submarine crust, becoming denser and denser, is slowly subsiding. The question has been raised recently as to whether the earthquake waves, or as (by a misnomer) they are more frequently called tidal waves, are not caused by the depression and upheaval of the dry land. There is no record in the late disaster in Sunda Strait of vessels having met these waves out at sea, though there are heartrending accounts of the terrible destruction witnessed upon reaching the shore ; as in some places the disaster was caused by a wave estimated to be fully 100 feet in height, it seems unreasonable to suppose that this could have travelled any distance without being observed by passing ships. Mr. Jabez Hogg has been carrying out some most interesting experiments on the rapid generation of animalculse. He took a few grains of dust from a garden wall, placed them in a shallow glass cell, and added a little filtered water. Presently under a powerful microscope were displayed signs of active life ; in ten or fifteen minutes two or three perfectly formed rotifers were seen darting about with expanding rotating discs actively feeding. At the end of 30 days fully twenty were observed, apparently in a healthy condition. The water was then allowed- to evaporate, when the microscope revealed nothing but fine dust, with no sign of living animalculae. The cell was then wrapped up in tissue paper, and for 30 days ■excluded from the light. On water being added again the same

results were observed, and this continued though the treatment was repeated frequently. Mr Hogg seems to think that these tiny creatures died and actually rose again; but it is more probable that, like certain other organisms,' their bodies contained ova, which were liberated by the death of the parent, and generated when the conditions were favorable.