Rensselaer Union, Volume 8, Number 8, Rensselaer, Jasper County, 11 November 1875 — MECHANICAL AND SCIENTIFIC. [ARTICLE]

MECHANICAL AND SCIENTIFIC.

—After filing a saw, place it on a level board and pass a whetstone over the side of the teeth until all the wire edge is off them. This will make the saw cut true and smooth, and it will remain sharp longer. The saw must be set true with a saw-set. —Scientific American. —Dr. Schlieman writes from Leyden, Holland, to the London Academy that he has become convinced, by new evidence treasured in the prehistoric portion of the museum of that city, that there never was any “Stone Age,” but that stone weapons and implements have at all times, even in‘ the remotest antiquity, been used simultaneously with weapons and implements of copper. _ —M. Emile Mer, who has attained considerable eminence as a physiologist among French botanists, says that a leaf that has attained its full growth only continues to exist on the condition of forming starch or glucose. When there is insufficient light or insufficient power to form these, what has been already elaborated is parted with by the stomata, the leaves turn yellow and die away. —Paint intended for outside work, which will not be protected by varnish, is mixed as follows: Crush the color if in lumps, and mix to a stiff paste with linseed oil, boiled or raw—the latter is preferable; then, if a dark color, add brown japan or gold-size, te the proportion of one-half pint to a gallon of oil; in a light color, use patent drier in similar quantities. — Western Manufacturer. —ln examining some portions of the flesh of a mallard duck, transmitted to him by Dr. Cones, Prof. Leidy found abundance of parasites in the interstices of the muscles. These were oval white bodies, one or two lines long and about one-third of a line thick, which, beneath the microscope, were ascertained to contain myriads of fusiform corpuscles, like minute Naviculae, measuring about one-fifteen-thousandth of an inch in length. Similar bodies were first discovered in fisSSjf by Prof. J. Miller and described by him as parasites, under, the name of Psorosperms. They have since been repeatedly observed in fishes and usually regarded as vegetable parasites. Prof. Leidy was not aware that any such organisms had been previously detected in birds. Though the mallard is not a fish-eating bird, as a yule, the individual may have become infected by swallowing a fish affected with these organisms.— New York Independent. —The voice of the stump-speaker is heard no more in all the land.