The two generations, as now appears, are not of distinct individuals, but are both required to make a complete individual. This paper will be sure to provoke criticism, and perhaps excite further research. Mr Hopkins has been enlightening the Geological Society 'On the Causes of the Changes of Climate at Different Geological Periods;' and assigns as one of the causes, the flowing of the gulf-stream in a different direction formerly to that which it follows at present, whereby the northern ice was brought down in great masses to form our glacial period.
Some of our savans are interested in Professor Simpson's communication to your Edinburgh Botanical Society, concerning his experiments on Alpine plants kept covered with snow by artificial means in an ice-house for several months. He finds that plants and seeds so treated sprout and germinate rapidly when exposed to the warm air of spring and summer. It appears also that chrysales similarly treated become moths in about one-tenth of the time required under ordinary circumstances; from which facts, and the celerity of vegetation in Canada and the arctic regions, Professor Simpson infers that, if we in this country were to keep our grain in ice-houses during the winter, we should get quicker and better crops, and avoid the ill consequences which sometimes attend sowing in autumn, or too early in spring. The subject is novel as well as interesting, to say nothing of its bearing on agriculture, and we shall be glad to see the promised results of further inquiry.
There are one or two other Scottish matters which may be mentioned. One is the discovery by Dr Penny of Glasgow, of potash salts in considerable quantity in the soot from blast-furnaces. In our iron districts, and among our iron merchants, it is undergoing that sort of discussion which savours of profit. Potash salts are so valuable, that if the discovery can be reduced to economical practice, there is no doubt that the hitherto wasted and unrecognised substance will be turned to good account. The other is the 'Platometer,' invented by Mr Sang of Kirkcaldy, described as a 'self-acting calculator of surface;' in other words, by using this contrivance, you may get the 'square measure included within any boundary-line around which a pen attached to the instrument may be carried'in the plan of an estate, or a map, for example, where the plots of ground are often extremely irregular in form, and difficult to measure, without much complicated calculation. When Arthur Young wished to ascertain the relative proportions of cultivated and uncultivated land in France, he cut up a map of the country, and weighed them one against the other; but the platometer would have helped him to a more satisfactory conclusion. The mode by which it effects its purpose is very simple, 'the essential parts being merely two axles, one of them carrying a cone, by which the computations are silently performed as the pen proceeds on its journey; and the other a small wheel, having numbers on it which tell the result in square measure.' The contents are given with considerable rapidity, and, it is said, with more exactitude than by any other process: the instrument, therefore, is practically useful as well as curious.
Among matters connected with the Académie, Prince Demidoff has asked for instructions as to how he may best serve the cause of science during a journey which he proposes to undertake into Siberia, accompanied by a scientific staff. The prince, who is proprietor of the richest malachite mines in Russia, has already made similar explorations in other parts of Europe, and published the results at his own cost, superbly illustrated, and has presented copies of the works to most of the scientific societies. He could not have better advisers for the purpose contemplated, than he will find among those to whom he has applied. Then a M. Rochas informs the Académie, that a photographic image on a metal-plate, transferred immediately to albumenised glass, may be reproduced and multiplied on paper in any number. Daguerreotypes of waves beating on the sea-shore have been exhibited, which were taken on glass thus prepared in a very minute fraction of a second. Add to this, a plan for a double line of submarine railway from Calais to Dover; a statement from M. Gaietta, that the aurora borealis is nothing more than spontaneously inflamed carburet of hydrogen; and a report from a learned anatomist, on the use, instead of the knife in amputation, of a platinum wire heated red-hot by a batteryand you may form a notion of the variety of communications that comes before the French savans . M. Peligot furnishes some details respecting silk-worms. He shews that in every 100 parts of mulberry leaves,
as supplied, the result is from 8 to 9 of worms, 36 to 40 of egested matters, and 45 to 46 of dry litter and waste. That the sixth part only of what the worms consume tends to their nourishment, the remainder goes in respiration and dejection; and that, with the data now obtained, it is possible to calculate the maximum weight of cocoons from a given weight of leavesit being from 60 to 70 in 1000. He shews further, that in years when leaves are scarce, the loss to the proprietors need not be total, for it is possible to keep the worms on short allowance, and collect their produce, though not so largely as when no privation exists. And what is singular, that the weight of silk is not in proportion to the weight of the worm or moth; heavy and light cocoons contain the same quantity of silk, the difference arises only from the different weight of the worms. Hence M. Peligot considers, that it would be well to destroy the females when first hatchedof course with a reserve for breedingand keep only the males, which eat less, and give an equal quantity of silk. But as yet the sexes cannot be distinguished, while in the worm state.