Do you know who invented the wheel-barrow V Why, no less a person than Leonardo de Vinci, a very famous artist, wlio lived about the time tlnit Columbus discovered America. He was, besides an artist, amusician, poet, painler, architect, aculptor, physiologist, engineer, natural historian, botanist and inventor. He is best known by his famous painting, "The Last Slipper," oue oí the grandest pictures ín the world. Isn't it strange that such a man should invent so simple and h unible a thing as a wheel-barrow! Yet it was a good boon to the world, especially to the laboring classes, and perhaps, in a different way and degree of course, it has done as much good as the grand painting. So don't let us despise doiig what seems to be little tliings, perhaus thev mav nrnv in ha great things, by and by, and perhaps, too, God wiU let ns do great things if we are not ashained of the smalt ones, What is commoner than the lead pencil, or more useful? Yet it was unknown before the days of "Good Queen Hess," as the English cali Qneen Elizabeth. Bat why do we cali these pencils black leadV The term is erroneous, for there is 110 lead in their composition, ïhe shining black substanee is plumbago, and is found in rocks in different parts of the world. Only one of these varieties is suitable to write with, and thisis called "graphite." The first mine of graphite was discoYcred in Oumberland the same yeur that Shakespeare was bom, it beingthe sixth year of the reign of Queen Elizabeth. This mine proved immediately valuable and lasted for about three hundred years, during which time England snpplied the world with lead pencas. But when tliis mine becaine exhausted, it was necessary to flnd sume way of inaking the impure plumbago, found in otlier places, available. A French invention solved the problem by mixing the plumbago, when powdered and purified with powdered clay, then mojstening and drying and pressing the masa vrying the treatinent according to the quality or hardress required in the different gií' Jes. The pencáis of the present day, though made of inferior plumbago, are much better than those made from the beautifu] Cumberland graphite infamer days. Thus does human ingenuity conquer difflculties, and reach adasired goalinspite of the obstacle3 and iniperfections in nature.