The instruments heretofore employed for leveling by surveyors and engineers, though excellent for the purpose and equally well adapted for carpenters and masons, in staking out foundations, or for farmers in leveling for ditching, etc., or for mechanics in general, were too costly for general use in their application to the purposes specified. The invention herewith illustrated can be placed in the hands of all who desire it, at one fifth the cost of the old styleof 1 eveling instruments, and for most of the purposes alluded to i s equallyas good. For all di stances withi n the scope o f unaid ed vision they are sufKcientlyaccurate. the front side of the frame in which the carriage rests is raised in order to bring the carriage on the opposite side of the frame down low enough to let the upper side of the bolt come under the edge of the saw. The movements in feeding are therefore as follows, the loft hand of the workman grasping the handle, M, raises the front side of the oscillating frame and depresses the bolt, while the right hand grasping the lever, N, moves it quickly backward and forward and the feeding is accomplished. Both movements are accomplished instantaneously and simultaneously. This level is made of iron, which is one reason why it can be afforded so cheaply. At one end it is provided with a sight having a small aperture with a short tube attached, to obviate the dazzling effect of the light, consequent upon reflection from the edges of the aperture. At the opposite end of the level is a ring with cross wires, so adjusted that the center of the sight aperture and the intersection of the wires are level when the bubble at the center indicates that the instrument is level. The level stands a circular graduated table, from the center of the under side of which is suspended a plumb in the usual manner. This plumb being adjusted over any point, as the corner of a building lot, and the fir,t line laid out, The Pliosphoroscope. If a person places a poker in the fire, everybody knows that a quantity of heat can be carried by it into the next room. Heat, then, like water in a jug, can be taken into certain things and carried awayfrom its source. Not so with sound; there is nothing yet known that will hold sound, and make itself tangible to our senses when taken away from that which produces it. Odors, like heat, are however absorbed by the hardest precious stones and polished steel. Neither the most delicate scales nor the most powerful microscope will discover anything on a diamond that has been near to musk or patchouly ; but their fragrance announces the fact of retention and emission of odor. Hitherto it has been an J axiom that when the light is put out we shall be in .the dark. Modern science now proves to us this need not always be so; on tlie contrary, we can now carry light away from» its source. We can, as it were, bottle up some light, and store it away in a dark cellar, assured that it is there, for we can see it. In proof of this assertion a pretty toy has been constructed for this purpose, called a phosphoro-scope or light-bearer, by Messrs. Harvey and Reynolds, of Leeds. It consists of an apparatus like a color-box, which contains, instead of paints, certain glass tubes, holding various light absorbers, such as sulphides of lime, strontium, barium, etc. By exposing this light box to the full flame of a gas-burner, or to the sun, QIoto the light of burning magnesium, light is absorbed to such an extent that any one can see whats oclock in the dark. Each tube, accord11 g to its contents, glows with light, but of different colors, some red, others blue; but the brightest is the green. The venders call this instrument » The Phosphoroscope, or a Trap to catch a Sunbeam.»$epm1ts Piesse.
This article was originally published with the title "Sibley's Improved Leveling Instrument" in Scientific American 21, 15, 232 (October 1869)