ARTS AND SCIENCE
FLATTENING OF THE EARTH.
At the Academy of Sciences at Paris, a memoir was read by Captain Duperrey, on the experiments made with the invariable pendulum, during the voyage of the Coquille round the world. He states that various experiments confirmed the fact of the flattening of the terrestrial globe, conjectured by several travellers, who had remarked that the number of oscillations which the pendulum made at certain places, differed from what had been observed in the extent of the same parallel. The principal anomalies observed by Captain Duperrey were at the Isle of France, Mons, Guam, and the Island of Ascension. At the Isle of France, the invariable pendulum (as had been remarked by M. Freycinet) made in one day, upon an average, thirteen or fourteen oscillations more than it ought, supposing the depression to be 1.305, according to the lunar theory. At Ascension, the acceleration, as noticed by Captain Sabine, was five or six oscillations, even supposing the depression to be 1.228. At other stations the difference was almost nothing; and in some, the motion of the pendulum was retarded. Such differences, Captain Duperry remarks, between the results of experiment and those given by theory, cannot be attributed to errors of observation. He is disposed to refer the cause of the phenomena, with Captain Sabine, to the want of homogeneousness in the earth, considered as a mass, or to the mere variations of density in the superficial strata. What tends to confirm this hypothesis, he says, is, that all observations show that an acceleration of the pendulum generally takes place on volcanic ground and a retardation on such as is sandy and argillaceous. A very important question to ascertain is, whether the flattening is exactly the same in both hemispheres. From the observations of Captains Duperrey and Freycinet, it appears that in the southern hemisphere it is 1.291, and in the northern 1.288; that is to say, it is sensibly the same, or 1.290 in both.
HABITS OF PLANTS.
The following curious observations on the habits of plants, were made by General Walker, in his address to the Agricultural Society of St. Helena, in February last:—"The functions of plants, as well as of animals, depend upon the air in which they live. I have observed that those of St. Helena, which have been brought from another hemisphere, are very irregular in their annual progress; many of them, in the development of their foliage, have adopted the law of nature peculiar to the country into which they have been transplanted. Others, more obstinate, remain faithful to their own habits, and continue to follow the stated changes to which they had been accustomed. They all appear to maintain a struggle either before they adopt the habits which belong to the seasons of their new country, or decide on retaining their relations with the old. In yielding to external circumstances, they appear to have different tempers. This appearance of contention is often observed in plants of the same species; they seem to hesitate and deliberate, ere they adopt the mode of performing the functions of life. At length when the decision is made, apparently not without pain and effort, we are at a loss to discover an adequate cause. An oak, for instance, which loses its leaves in a St. Helena winter of 68 degrees, scarcely experiences the difference of temperature, which, reasoning by analogy, could cause that change. It would have continued to maintain inflexibility, in its original climate, its old habits, though exposed to far greater irregularity and severity of climate. But though the law is obeyed by many plants, it does not determine the periodical changes of the whole, nor do they all submit to it with equal readiness and regularity. It would add, I conceive, to the natural history of vegetation, and improve our knowledge of the geography of plants, were the facts concerning their habits and changes, under different temperatures, carefully collected."