Rensselaer Republican, Volume 17, Number 48, Rensselaer, Jasper County, 6 August 1885 — POPULAR SCIENCE. [ARTICLE]

POPULAR SCIENCE.

Floating bricks are made of a very light silicious earth, clay being sometimes added, io bind the material together. They can be made so light that they will float on water, while their strength equals ordinary bricks. The opinion is entertained now by many men of science that the art of making artificial stone for structural purposes is prehistoric, and that the Pyramids were, in fact, built of artificial blocks manufactured from the surrounding plain. A' curious observation has been made by Dr. Copeland, and English astronomer. While watching one of Jupiter’s satellites he was able to see it pass over its own shadow on the planet. For this to have happened, the sun, the earth, the satellite, and tne part of Jupiter’s disk occulted must have been all in one straight line, and, as seen from Jupiter, the earth must have appeared making a transit across the sun. In speaking of minor ailments connected with digestion, Dr. Lander Brunton said recently that headaches were usually dependent either upon the presence of decayed teeth or of some irregularity in the eyes, more especially in the focal lengths between the two. As persons who were subject to headaches in their youth grew older, bilious headache was very apt to be replaced by giddiness, and this change came when people needed spectacles. A German entomologists, F. Dahl, claims that spiders have perfect sight only at very short distances. Their sense of touch is consequently remarkably well developed. Their smell is so good that they can distinguish odors, and their hearing is excellent. Some of them show a.remarkable instinct in building tbeii^ebs— even their first — in perfect gefflnetrical lorm. A reflective power is evinced by their refusal of all kinds of tough which have been once attacked unsuccessfully. RfiEEM.of the Smithsonian Institute, has contradicted much of the popular belief concerning snakes. The venomous hoop snake, which takes its tail in its mouth and rolls along like a hoop, and the blow snake, the breath of which is deadly, exists only) in the imagination. The idea that serpents sting with their tongue is erroneous. An impression prevails that the number of poisonous snakes is great, but in North America there are but three species—the rattlesnake, the copperhead or moccasin, and the corah Snakes do not jump; they reach suddenly forward, perhaps half the length of their bodies.