Vol. 1 No.8 - Pg.1

DECLIVITY OF RIVERS.—A very slight declivity will suffice to give the running motion to water. Three inches per mile, in a smooth straight channel, gives a velocity of about three miles an hour. The Ganges, which gathers the waters of the Himalaya mountains, the loftiest in the world, is, at eighteen hundred miles from its mouth, only eight hundred feet above the level of the sea; that is about twice as high as St. Paul's church in London, and to fall these eight hundred feet, in its long course, the water requires more than a month. The great river Magdelena, in South America, running for a thousand miles between two ridges of the Andes, falls only five hundred feet in all that distance. Above the commencement of the thousand miles, it is seen descending in rapids and cataracts from the mountains. The gigantic Rio de la Plata, has so gentle a descent to the ocean, that in Paragua, fifteen hundred miles, from its mouth, large ships are seen, which have sailed against the current all the way, by the force of the wind alone; that is to say, which, on the beautifully inclined plane of the stream have been gradually lifted by the soft wind, and even against the current, to an elevation greater than that of our loftiest spires.—[Arnot's Physics.

SPECIMENS OF THE ARTS IN RUSSIA.—A magnificent vase of sea-green jasper has lately arrived at St. Petersburg, and been placed in the Palace of the Hermitage, having been cut by order of the Emperor in the mines of St. Colywan. The London Athenæum mentions the work, and states that its dimensions are colossal, its diameter being fifteen feet, and its weight, including the jasper pedestal, 418,898 pounds. The upper edges are sculptured in relief and adorned with chasings of the most exquisite finish. In 1829 commenced the work of extracting the block from the quarries of the mountain Rewenwaga, near Colywan; in 1831 it was hoisted and dragged to the work-yard. For its transportation to St. Petersburg, 550 peasants, and 120(increased in places to 160)horses, were required. As it could not pass over the bridges, it had to be drawn across the rivers in winter, on ice four feet in thickness. Several times it broke through, but preparations had been made for such an event, and it was recovered from the water unmutilated. All the workmen employed, either in the work of art or in its conveyance, have received rewards from the Emperor.

THE EYES OF INSECTS.—How wonderfully constructed is this beautiful organ of insect vision!(How admirably adapted to the necessities of insect life! The gaudy dragon fly, presenting as he does, such a conspicuous and tempting show of colors to the active swallow, eludes the feathered enemy by superior agility of flight. Mere agility, however, would avail nothing without the aid of powerful eyes. Accordingly nature has given him somewhat more than twelve thousand bright and piercing ones, some looking upwards, some downwards, some backwards, and some on either side. In the ants, there are fifty of these faces or eyes; in the horse fly four thousand; in butterflies, no less than seventeen thousand three hundred and fifty-five have been counted—nay, in some coleopterous or scaly winged insects, there have been numbered no less than twenty-eight thousand & twenty-eight.—[True Sun.

BRAZING SOLDERS.—Workers in metals will find the following order of the hardness of solders useful:—3 parts copper, 1 part zinc, very hard; 8 parts brass, 1 part zinc, hard; 6 parts brass, 1 part tin, 1 part zinc, soft. A common solder for iron, copper, and brass, consists of nearly equal parts of copper and zinc.