The Arkansaw traveler., 1889-09-28
COMPILED roa rm AnxAxsAw rnkvmm.
 SCIENTIFIC MISCELLANY.

A French physician reports cass in which the usual incubation period of measss-twelve to four- teen days-seems Co have been considerably ex- ceeded In two cases the disease appeared as lesst twenty days after exposure and in the third cas im nineteen days
 vegetable cartridge she'll, which is entirely consumed In firing, is . French novelty. With this shell the cartridge has scarcely half the weight of metal cartridge, the cost is considerably Is@ and the inconvenience of removing the shell sftsr each shot Is avoided.
 FooD FROM IRoN.-In new treatise on manures, MT. A. B. Grifiths states that the process of con- verting iron into Bessemer steel results In the dim ination of basic sag, containing from 14 to % per cent of phosphoric acid. Reduced to an im- palpable powder, this slag Is valuable plant food and as manure the 900 tons of the sag obtained yearly in England should produce at least 100000 tons of hay, or sufficient for feeding 750000 head of cattle.
 AN INGENIOUS ELECTRIC LAMP.-A Belgian iu- ventor, M. Henri Pieper, has devised new and very simple incaudesoent lamp. thin pointed rod of carbon, placed vertically, rests upon two horizontal copper rods about quarter of an inch apart, and forms . bridge between them. The cur rent passes between the copper rods through the carbon, rendering 1t incandescent. Springs move the copper reds slightly when the carbon is con- sumed and prevent the breaking of the circuit. TURNED IN NATURES MACHINE sHor.-Two al- most perfect spheres about four inches in diameter lone black and of vegetable origin and the other white and mineral product-were lately exhibited to the Geneva Society of Physics and Natural His tory. Both were remarkable having been pro- duced by mechanical movement The black ball was of two formed by the slow rolling to- gether of dust in cavity of the oak shaft of an old mill-wheel and the white ball was . calcareous pebble found with many others In c grotto trav- ersed by torrent flowing into the Rhone. PROTECTIVE PAINTs.-The Dutch State Railways have made series of experiments to determine ex- actly the relative resistance to weather and sea water of various pigments. lead paints, being more adhesive to metal and more elastic, were les affected by atmospheric changes than those com- posed of the brown oxides of iron. The protec- tion afforded by any paint was found to be in- creased by pickling the plates in hydrochlorc acid before its application Admixture with the oxide of some electro positive metal such canstic lime or soda, prevented corrosion by sea water; but only magnesa proved long serviceable, as the efa- ciency of the others was diminished when their alkaline properties were neutralized by cArbonic acid, which they, unlike magnesia, readily absorb. The magnesia not only protected the iron from galvanc action, but had effect on the anti-fo | ing qualities of the paint
 STONE CUTTING BY BAND-SAw.-The "heliooidal wire cord"-hrst applied by M. Panlin Gay, of Marseilles-is coming into use effective plan | for cutting stone in many European quarries. An engine drives continuous wire cord of about one sixth of an inch in diameter, composed Of three mild steel wires twisted together, this cord being guided by grooved pulleys and stretched by weighted truck on an inclined plane. The cord is placed upon the stone, and the cutting mnd is di- rected with water along the course chosen. Stonee 90 hard as hitherto to be worked only by means of pick or chisel are readily sawn, an hourly cut of one inch in granite four inches in marble being regularly obtained in blocks fifteen sixteen feet long. cord 150 yards long will cut about seventy feet deep in blocks fifteen feet long before being worn out. Not only may blocks of stone be saved, but they may be cut out of the solid rock by sink ing shaft to introduce the pulley-carriers
 TREES IN LIGHT AND SHADE.-Trees nearly d. ways develop best in full sunlight, states Prof Fernow of the United States forestry department, but their capacity of developing under shade varies greatly. The yew will thrive in the densest shnos the beech will grow with considerable energy in