Page:Popular Science Monthly Volume 30.djvu/740

718, the Anemone sulfurca and the Ranunculus glacialls are taken from the Alps by ten thousand at a time; and a lot of four thousand edelweiss was recently shipped to America. If the plants are not taken up with proper care, eighty out of a hundred of them will probably perish, and fifty more will be trampled upon or mutilated in getting the hundred. The Swiss Association does not object to the collecting of the plants; it only wants them collected in such a manner that no danger shall be incurred of destroying or diminishing the species. It seeks to point out how this may be done, by selecting the season when removal will involve no danger to the life and vigor of the plant, and especially by insisting upon a more general adoption of cultivation and reproduction by seed. It has established a garden of acclimatation near Geneva, where the seeds of mountain-plants are raised to be sold at a moderate price, from which it has already obtained good results; for many persons who used to plunder the mountains now go to it for seeds. It does not confine its attention to the plants of its own country, but keeps a good lookout also for the well-being of rare species in other lands; and has agents in Mexico and Brazil to intercede with the authorities for the institution of measures to secure the preservation of the cactuses of the former country and the orchids of the latter.

Glacial Action in East Africa.—Mr. H. E. O'Neill, British consul at Mozambique, in a description of Eastern Africa, between the Zambesi and Rovuma Rivers, speaks of the frequency with which one encounters evidence of glacial action as a very interesting point to the traveler in that country. "I have met with it," he says, "upon the Namuli range, in the Inagu Hills, and again much nearer the coast, among a small block of hills called the Tugni, You see it everywhere in the smooth, dome-shaped tops and polished precipitous sides of the hills of the country, but the clearest evidence is afforded by the more striking spectacle of huge detached blocks lying across the summits of peaks—blocks many tons in weight, which could never have been carried there by any other known physical agency than that of ice."

Our Oldest Herbaria.—President William Carruthers, in the Biological Section of the British Association, spoke of the value of herbaria, or collections of dried specimens of plants, for supplying the most certain materials for the minute comparison at any future time of the then existing vegetation with that of our own day. We have now collections in England about two hundred years old that have been used for that purpose. Dr. Schweinfurth has obtained specimens, which were originally deposited in the form of offerings, from Egyptian tombs, four thousand years old, which are as satisfactory for the purposes of science as any collected at the present day, and which consequently supply means for the closest examination and comparison with their living representatives. The colors of the flowers are still present, even the most evanescent. The chlorophyl remains in the leaves, and the sugar in the pulp of the raisins. Dr. Schweinfurth has determined fifty'-nine species, some of which are represented by fruits, others by flowers and leaves, and the remainder by branches. Mr. Carruthers also referred to the deposits discovered at Cromer, and the remains which exist of pre-glacial flora, and came to the conclusion that the various physical conditions that necessarily affected those species in their diffusion over such large areas of the earth's surface in the course of, say, two hundred and fifty thousand years, should have led to the production of many varieties, but the uniform testimony of the remains of this pre-glacial flora, so far as the materials admit of a comparison, is that no appreciable change has taken place.

Coal-Mine Gas-Explosions and the Weather.—Mr. H. Harries remarks, in "Iron," that though a connection is believed to exist between fire-damp in coal-mines and atmospheric changes, its nature is not well understood. The rule is probably analogous to that which controls weather-changes, which are not indicated by definite points in the barometric scale, but by differences in pressure between neighboring places. He thinks, therefore, that it is desirable to ascertain whether the presence of gas in mines is, like the weather, distributed in areas, and