Science Siftings

New Zealand Tablet, Volume XXXVI, Issue 6, 6 February 1908, Page 35

Science Siftings

By 'Volt*

! . An African Lake. . , Lake Tchad, in Africa, is reported by two French explorers to be 185 miles long and 89 miles wide, yet only 25 feet deep in its deepest part, and only five feet on its eastern side. It has 80 islands, some barren, oth- . ers only pasture land, and some covered with forests .and 'millet plantations and ha. ing a total population of about 50,000. Origin of the Cannon. ■> It is a curious fact that the first cannon was cast' at Venice. It was called a ' bombard,' and was invented and employed by General Pisani in a war aeainst the Genoese. - The original bombard, which bears the date of 1380, is still preserved, and stands at the feot of Fisani's statue at the arsenal. The ; bombard threw a stone 100 pounds in weight. Another Venetian general, Francisco Barde, improved it. until he was able to handle a charge of rock and boulders weighing 3000 pounds. It proved disastrous, to him however, _J or one day during the siege'- of. Zara, while he was operating his terrible engine * he was hurled by it over the walls and instantly killed. Practical use of Lava. Residents of the district, round Vesuvius have put to practical use the lava which has flowed from the volcano in past and rcc.nt eruptions. Naples and its vicinity appear to> be a world of lava. The streets are paved with it. There are lav& staircases and statues, draining troughs, tric-a-brac and even jewellery. The guides make profit out of it Jbty pressing coins or other objects on partly cooled fragments anl seil.ng these to visitors. On the ashy sides of the mountain there is enough lava to build a city. ln> appearance it resembles a shoreless frozen sea of dull Ike, that shimmers' stiangely purple in some lights. Three Months of Sunlight. , The three months of almost continuous sunlight each summer in Alaska has an odd effect on most jewcomers. A man accustomed to seven hours' sleep each night nncfe upon gang there that he cannot easily adjust himself to the alt- red condi iens. Most people get sleepy wh n the dark comes, and do not think of sleeping in dayLjrht. As a result men go day after day when first in the North with -little inclination to sleep. A man has to train himsjf in Alas..a.togo to bed with the sun shining high in the sky. Those who need darkness m order to slumber have to pin blankets over the windows and go to a great d^al of extra trouble to produce it- ' Eagles and Their Prey. Ornithologists are inclined to discourage the idea that eagles are in the habit of attacking large animals, but a contest witnessed by an observer dispels such a theory. The battle was between an eagle and a stag. The bird singled out from a herd one particular bucK, which it succeeded in driving from the rest. It struc* the animal with its powerful wings, knockang it aown, and finally killed it. A still more remarkable spectacle is well authenticated. An eagle attacked a fawn in the highlands of Scotland. Ihe .cries of the little one were answered by .its dam, whuh sprang upon the eagio and struck it repeatedly with -its forefeet. Fawn, deer, and eagle rolled down a declivity, tbe biid was dislodged from its hold, and the fawn rescued. Many traditions are extant as to the carrying off of children by eagles.- The most recent case bearing close scrutiny is one vhich happened in South Africa. A Boer farmer whose" stock had been harried by eagles lay m ambush for the robbers and saw one of them descend and carryoff the five-year old child of one of the Kaffir servants. He shot the bird, which, with, the child still clutched in its grip, fell into a thorn bush. The bird was dead,^ but the child was little hurt. Two eagles will stalk a covert in concert. While >one conceals itself the other beats about the .bushes with great screaming, driving out its quarry, for the hidden eagle to swooo down upon. An even more insidious method has 'been observed.. An eagle seeing a sheen on the .edge of - a precipice flew - at it, screaming shri'ly, and with a forceful beat of wing hurled it into the valley below, where it could de^ your ft at its lpisure. In the light of such records there good reason for believing; the "legend of- the eaele drop^ pins *• tortoise on the hfald head of Aeschylus, the Greek J>6et f and so causing, death, .-~. -~ "