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REFINING OF METALS 465 REFLECTION mitted to the popular vote, if demanded within 90 days after their publication by 30,000 voters, or by the government of eight cantons. During the 17 years, 1874 to 1891, out of 149 laws, 27 were referred to the people; of these 15 were rejected. The referendum has worked so well that it has conquered all opposi- tion to it, and it is now generally re- garded as a check on hasty and class legislation. It will be observed that the essence of it is that it submits to the people a single and clear issue upon which they may give their decision. There exists also an obligatory referen- dum in eight cantons, where every law and every expenditure beyond a fixed maximum must be submitted to the mass of the electors, and it is not necessary that a demand for this submission to the electors should be made. In Great Britain what may be termed a kind of local refer- endum with regard to the "Adoptive Acts" was set up by the Parish Coun- cils Act of 1894. There is a growing demand in the United States for the gen- eral introduction of direct legislation by means of the referendum, and in several places the system is practiced. REFINING OF METALS, the proc- esses by which the various metals are extracted from their ores, and obtained in a state of purity. See the articles on the several metals. REFLECTING CIRCLE, an instru- ment for measuring altitudes and angu- lar distances, invented by Mayer about 1744, and afterward improved by Borda and Troughton. In principle and con- struction it is similar to the sextant, the graduations, however, being con- tinued completely round the limb of the circle. Also called a repeating circle. REFLECTING GALVANOMETER, Sir William Thomson's insti'ument, con- sisting of a very small magnet, made of a piece of watch spring, suspended between two flat bobbins of fine insulated copper wire. The magnet carries a very small concave mirror, which is adjusted by means of a directing magnet to throw the rays of light, issuing from a lamp and reflected from the mirror, on the zero of a horizontal graduated scale when no current is passing, or when two equal and opposite currents neutralize each other. In any other case the vibrations of the magnet cause the image to be deflected to the right or left of zero by an amount proportional to the force and duration of the current. REFLECTING MICROSCOPE, a form of microscope first proposed by Newton, in which the image formed by a small concave speculum may be viewed either by the naked eye or through an eyepiece. The object is placed outside of the tube of the microscope, and reflects its image to the speculum by means of a plane mir- ror, inclined at an angle of 45° to the axis of the former. REFLECTING TELESCOPE, a tele- scope in which the rays are received on an object-mirror and conveyed to a focus, at which the image is viewed by an eye- piece. REFLECTION, that which is reflected, or produced by being reflected; an image given back from a reflecting surface. Also the act or habit of turning the mind to something which has already occupied it; thoughtful, attentive, or continued consideration or deliberation; meditation, thought. A surface on which a beam of light falls may be either rough or smooth. If it be rough, the greater part of the incident light is irregularly scattered by the innumerable surface facets, so as to be reflected or dispersed in all direc- tions; if it be smooth, a proportion (but never the whole) of the incident light is regularly reflected or turned back in definite paths. A smooth, dustless mir- ror is not visible to an eye outside the track of rays reflected from it. If the polished surface be that of a transparent substance (e. g., glass) optically denser than the medium conveying the light to it, compai-atively little light is reflected; but the more oblique the incidence, the smoother the polish, and the greater the difference between the optical density of the glass and that of the medium in which it is immersed, the greater the proportion reflected. Thus less light is reflected from glass under water than from glass in air; and conversely, if the light travel in the denser medium and strike the bounding surface between it and a rarer medium — as where light ascending through water strikes its upper free surface — it will, if its ob- liquity of incidence exceed a certain limit, be almost totally reflected; the small loss that ensues arising wholly from absorption, while no light is trans- mitted into the air above. This may be shown by holding a clear tumbler of water above the head; the image of ob- jects beneath is seen reflected in a bright mirror surface; and a phenome- non of the same order is seen on thrust- ing a test tube containing air below the surface of water, when it will appear to have a luster like quicksilver. If the reflecting surface be that of an opaque body the bulk of the incident light is reflected, a percentage being lost by absorption. What has been said about light applies equally to ether undulations