Page:Popular Science Monthly Volume 49.djvu/591

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FRAGMENTS OF SCIENCE.
571

toward one of those which were fixed, and hovering a few inches away from them, but only for a few minutes. The fixed insect turned its abdomen a few degrees, when the second immediately settled on the wire in the same attitude as the others, into an absolutely motionless position. The distance between the insects varied from about four to twelve inches, the average being about eight inches, while no two were closer together than four inches. They never came with full force upon the wire, but were seen pouncing from all points upon the settled individuals, when the proceedings described above followed; the insect always fixing itself so as to have a little clear space toward the west. Once settled, the dragon flies remained motionless, as if hypnotized by the reflection of the sun from the wire in front of them. Occasionally one would leave the wire, but always to settle itself at once a few yards farther on; none went away upon a long flight. M. Barrels found the wires thus occupied by dragon flies—he estimates that there were sixty thousand of them—for eight or nine miles, to where the line turned abruptly toward the south. The position of the insects, with their heads turned west, indicates that they were attracted by the sunlight; and the space which they all kept to the west of them was that required to afford a clear opening in which the reflection could take place.

Characteristics of Alpine Plants.—As described in Garden and Forest by M. H. Correvon, of the Alpine Garden, Geneva, the vegetation which thrives on great altitudes, like those of the Alps, Andes, Himalayas, and the mountains of Oceania, shows a distinct individual character readily noticeable. The plants are usually stunted, short-stemmed, or stemless, with flowers relatively exaggerated in size. The large flowers are almost sessile, with hardly apparent and only slightly developed foliage, which at a very high level is often clothed with a fine, close down, so as better to withstand the effects of cold nights. In many cases the foliage is glabrous, when it is also usually coriaceous (with tissues especially adapted to resist the frosts of Alpine climates); and the leaf, of a firm, close, thick texture, is provided with a solid epidermis and covered with a waxy coating, which enables it to withstand the effects of the sun as well as those of an excess of humidity. Species that grow in the shade and in well-protected spots are, however, not thus armed. Their foliage is soft and delicate, whereas woolly plants—take the Edelweiss and species having smooth, generally thick and glossy leaves—are usually encountered on arid, unsheltered slopes. Flora of altitudes exposed to the heat of the sun generally produces large, brilliantly colored flowers; while that of shaded situations exhibits very small, pale blossoms, entirely out of proportion to the size of the plant. The influence of the sun and its effect on vegetation are more striking here than elsewhere. Annual species, so abundant on lower levels, are rarely met with in Alpine zones. The short summer there does not permit them to accomplish the complete cycle of their existence in a single season. Alpine plants are always branched from the base with perennial root-stock and stems spreading on the ground, whereby the plant secures protection against inclement nights and severe days. All the activity and energy of the plant is brought to bear on the development of the flower and the reproductive organs. Owing to the conditions under which they thrive, Alpine plants require sometimes several years to accomplish the cycle of their existence, and need more than a single season to produce flowers and seeds. The flora of polar countries has a very different aspect from that of the mountains, though many species are common to both. The polar sunlight, though more constant, is less intense and more diffuse than that of the temperate regions in which most of the mountain flora has its home. The effects of the difference are seen in the plants and flowers.

Holy Wells.—Curious superstitions connected with holy wells are illustrated in M. and L. Quiller-Couch's book about those of Cornwall. Many if not all of these wells date as holy from pre-Christian times, and as it was not practicable or even possible to nullify the people's faith in them, the missionaries had to Christianize them by renaming them and dedicating them to some Christian saints, and there are now few English wells that have heathen names. Heathen rites