Modern Electrical Illumination |
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ampere angle arc lamp arranged artificial horizon Average Foot-Candles axis beam blue brackets BRITISH EMPIRE EXHIBITION building bulb candle-power cent centre circuits Clear Lamp colour decorative degrees diameter distance EDISON SCREW effect efficiency equipment feet flasher floodlighting foot foot-candles gas-filled lamp glare glass green illuminating engineer illustrated in Fig installation intensity of illumination intensity of light interior lamp filament lanterns layer length light emission light rays light source lighting units Lumen or Candle lumens luminous luminous flux method mid-span minimum number of lamps object obtained opal operation pigment plane plane of reference polar curve position produce projectors rated Reflection Factors reflector fitting retina seen shadows shown in Fig side spacing square standard street lighting suitable surface switches TABLE Test Quantity theatre thoroughfares tion tungsten vertical violet voltage Volts Walls Medium Walls watt-hours watts width window wire yellow
Popular passages
Page 108 - Steel and iron mills, bar, sheet, and wire products: Soaking pits and reheating furnaces...
Page 107 - Medium bench and machine work, ordinary automatic machines, rough grinding, medium buffing and polishing...
Page 197 - Fig. 64, is a curve such that every point in the curve is equally distant from the directrix KL and the focus F. The focus lies in the axis AB drawn from the vertex or head of the curve A, so as to divide the figure into two equal parts. The vertex A is equidistant from the directrix and the focus, or \e=AF.
Page 115 - Use upper column headings for direct-lighting units ; for semiindirect and totally indirect units choose column at bottom of page. Wherever the circumstances are such that the room index falls between the two given letters, interpolate or use the letter first in alphabetical sequence. Room Width.
Page 402 - Coefficient of reflection, — the ratio of the total luminous flux reflected by a surface to the total luminous flux incident upon it. It is a simple numeric. The reflection from a surface may be regular, diffuse or mixed. In perfect regular reflection, all of the flux is reflected from the surface at an angle of reflection equal to the angle of incidence. In perfect diffuse reflection the flux is reflected from the surface in all...
Page 221 - ... made for the illumination from the ship of the lifeboats when alongside and in process of or immediately after being launched.
Page 198 - Place a straight-edge to the directrix EN, and apply to it a square LEG. Fasten to the end G one end of a cord equal in length to the edge EG, and attach the other end to the focus F; slide the square along the straight-edge, holding the cord taut against the edge of the square by a pencil D, by which the parabolic curve is described. 56. To draw a tangent to a given parabola through a given point. Case 1. The point is on the curr
Page 405 - I/TT candles per square centimeter of projected area. It is the average brightness of a surface emitting or reflecting one lumen per square centimeter, or the uniform brightness of a perfectly diffusing surface emitting or reflecting one lumen per square centimeter. For most purposes, the millilambert, 0.001 lambert, is the preferable practical unit.
Page 110 - In the chart the best rating given is A+, which denotes the highest degree of excellence, while D, the lowest, indicates that an installation of units so rated in any particular will very likely prove unsatisfactory in an installation where this factor is important.
Page 407 - Saturation of a color is its degree of freedom from admixture with white. Monochromatic spectral light may, for purposes of measurement, be considered as having a saturation of 100 per cent. As white light is added, the saturation decreases, until, when the hue entirely disappears, the saturation is zero. White, therefore, is the limiting color having no hue and zero saturation.