Rensselaer Union and Jasper Republican, Volume 8, Number 37, Rensselaer, Jasper County, 1 June 1876 — MECHANICAL AND SCIENTIFIC. [ARTICLE]

MECHANICAL AND SCIENTIFIC.

—Dr. Edward Smith, author of a work on “ Foods,” thinks that condensed milk is not a suitable food as a substitute for pure milk for infants. It is niore fattening, but less nourishing, and greatly reduces the child’s power of resisting diseases. Dr. Smith states that children brought up on impure London fed cows* milk will resist an attack of acute disease better than children fed on condensed milk. —Heracline is the name given to a new blasting powder, invented by Dickerhoff, aud which has been tried with success in the coal mines of France and Austria. It is composed of picric acid, saltpeter, nitrate of soda, sulphur and sawdust. The gases produced by its combustion are not injurious, it is claimed, and it burns com- ■ paratively slowly, so that it only tearsapart the masses blasted, but does not hurl them violently about. “—£ varnish for small or large metallic articles can be prepared, says the Industrie Blatter , in the following manner. Finely pulverized gum sandarac or mastic (the latter, however, is too expensive for some uses) is dissolved in strong potash lye until it will dissolve no more. The solution is diluted with water aud precipitated with a solution of a copper salt, either sulphate or acetate. This green precipitate is washed, dried and dissolved in oil of turpentine. This produces a fine, green varnisb,whichdoes not change under the effect of light, aud is said to be especially useful for ornamental iron work.

—As Paris green is a most dange 3 % and deadly poison, great care is necessary in mixing it for any purpose, owing to the fine dust which arises—this being inhaled and also rapidly absorbed by the pores of the skin, especially if the person using it is in a state of perspiration. Malignant sores are not unfrequently caused by scratching the skin when itching or irritating from handling the green. As a remedy, hydrated peroxide of iron is recommended—the sores to be covered well with this, as with a salve, and a teaspoonful in a wine-glass of water to be taken twice a day internally while working with the green. —Exchange. —Sobrero, the inventor of dynamite, in a recent communication to the Academy of Turin, designated two of the operations in the manufacture of dynamite as especially dangerous: first, the mixing of the nitro glycerin with the infusorial sil ica (kieeelguhr), and second, pressing the mass into molds for cartridges. In both cases an explosion may easily be caused by friction and pressure. Nobel recommends the following process as far safer, namely, to mix the silica with water to a dough, then press it into cartridge molds and dryi perfectly. These cartridges are then put into nitro-glycerin, which they absorb into their pores, the absorption being aided by exhausting the air. Sobrero made his experiments with infusoria of Italian origin which can be easily made into cartridges that will absorb as much as seventy-five per cent. oOheir weight of nitro glycerin.— Scientific American.