Page:Popular Science Monthly Volume 27.djvu/737

Rh we reach the year 1789 that we find the germ of the science, in a paper by Benjamin Franklin, under the somewhat timid title, for so bold a meteorologist, of "Meteorological Imaginations and Conjectures." This is followed by contributions from Lamarck, Saussure, Playfair, and Humboldt. The number of references to the year 1800, when Humboldt's name is first mentioned, is only three, while in 1880 the number has increased to eighty-four. America, as the country affording most facilities for systematic observations, has the leading place in the list all the way through.

Enlargement of the Sun and Moon in the Horizon.—Various hypotheses have been proposed to explain the apparent enlargement of the sun and moon in the horizon over the size they seem to present at the zenith. Experiments recently made by M. Stroobant, in Belgium, indicate that the cause of the phenomenon is a physiological one. In a darkened room, M. Stroobant had fixed to the ceiling two electric stars about eight inches apart, and on the level of his eye two similar stars, the distance between which could be varied at pleasure, while the observer's eyes were at an equal distance from either pair. When the pair of stars on the level of his eye were so adjusted as to appear at the same distance as the pair in the ceiling, they were proved on measurement to be only six and a half inches apart. He then transferred his observations to the-actual stars, selecting pairs at sensibly equal distances apart in the horizon and in the zenith, and afterward measuring their real angular separation as marked on the celestial globe. The apparent separation of the stars in the horizon was increased in almost precisely the same degree, the ratio of the real distances, which seemed to the eye to be the same, being as 100 in the zenith to from 79·5 to 81·5 in the horizon.

The Vegetation of Gutter-Stones.—Dr. Hugo Winnacker, who devoted eleven full months to the study of the subject, has published a paper on the "Vegetation of Gutter-Stones and its Relation to Infectious Diseases." The subject is one of no little importance, for, if the gutters of our streets really harbor infectious plants or germs, they are capable of being very dangerous agents for the spread of disease. Parts of them are exposed to being dried every day, and when they are in that condition the germs might be taken up by the wind and scattered everywhere, to become active whenever they are supplied with moisture. Dr. Winnacker has found that the vegetation of the gutter-stones consists of green algae and fungoids. The algæ are harmless and even beneficial, for they grow over the fungoids and at their expense, and help to keep them down. They should therefore be encouraged by not removing them, and by flushing the gutters, so as to supply them with the elements favorable to their nutrition. Most of the fungoids likewise appear to be harmless, but some of them may be dangerous, and, as it is hard to distinguish their qualities, it is well to be on the watch against them. Two of the fungoid forms, quite abundant at Göttingen, are especially described. One, a micrococcus and ferment, grows in a reddish-brown coating from early in the spring till late in the fall. Another, a mold, grows in thick masses all the year round. The character of the vegetation may be different in different cities.

Difficulties of Underground Telephony.—The difficulties in the way of at once laying the telegraph and telephone wires underground in London are succinctly stated in the "Saturday Review." The inductive effects in the telephone wires are already annoying enough, when there is room to spread the wires in the air. They would be greatly multiplied if the conductors were bunched together, as they would have to be, to be put in a tube underground. The retardative effects would also be largely increased, to a serious extent, in fact, in the case of the telephones, for they depend upon abrupt and rapid changes in the strength of the current, and these would be so far nullified as seriously to impair the clearness of the articulation if the line were of any considerable length. The expense of construction would be largely increased by the necessity of coating the wires; while the coating, mainly composed of gutta-percha, is perishable, and constantly giving rise to "faults." A system of sub-ways, like the