Lectures: On Illuminating Engineering Delivered at the Johns Hopkins University, October and November, 1910, Volume 2John Hopkins Press, 1911 - Lighting |
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Common terms and phrases
achromatic angle arc lamps artificial light average brightness building burner candle ceiling cent Class color color vision consideration considered consumer cost cubic feet cubic foot dark diffusion direct distance distribution of light effect efficiency electric lighting equipped fixtures floor flux of light foot-candles gas lamps gas mantle glass globe height hemispherical candle-power horizontal hour Illuminating Engineer incandescent lamps inches indirect lighting installation intensity of illumination interior inverted lamps light source lighting units lumens luminous mantle maximum mean spherical meter meter-candles method municipal number of lamps objects obtained opal operation outlets photometric placed plane polar curve practically pressure prismatic reflectors prisms radiation rays reflection retina scale sensations shade shown shows specular reflection square street lighting supply surface tests tion total flux tungsten vertical vision visual acuity visual perception walls window
Popular passages
Page 998 - If any consumer to whom a meter has been furnished, shall request the commission in writing to inspect such meter, the commission shall have the same inspected and tested; if the same on being so tested shall be found to be...
Page 999 - TESTING METERS AT NORMAL LOAD A. Residence and apartment lighting 25% B. Elevator service 40% C. Factories (individual drive), churches and offices 45% D. Factories (shaft drive), theaters, clubs, entrances, hallways and general store lighting 60% E.
Page 952 - An Act to provide revenue, equalize duties, and encourage the industries of the United States, and for other purposes.
Page 986 - Other services must be rendered at the moment the person served desires. For example, the Metropolitan District Railway must be prepared to bring in its thousands of passengers to the City at the beginning of the day and to take them back in the evening, and for the rest of the day it must be content to be comparatively idle. In this case the services cannot be stored. The line must be of a carrying capacity equal to the greatest demand, and if this be great for a very short time the total return...
Page 582 - At the two poles stand the extremes of white and black ; upon the vertical axis, between the poles, are arranged the remaining sensations of light. Round the base of the figure lie all hues of a middle tint and of maximal chroma. Between base and poles lie the same hues in all their further variety of tint ; all are still of maximal chroma, though the chromatic maximum decreases steadily, above and below. If we cut into the pyramid, from any point on the outside to a corresponding point upon the...
Page 986 - They also now realise that if they are to be ready to give a supply at any moment, they must burn much coal and pay much wages for however short a time the supply is actually taken. Indeed, the term
Page 998 - ... the expense of such inspection and test shall be borne by the corporation ; if the same on being so tested shall be found to be correct the expense of such inspection and test shall l;e borne by the consumer.
Page 999 - When a meter is found to be connected to an installation consisting of two or more of the above classes of loads, the normal load shall be obtained by multiplying the connected watt load of each class by the percentage specified above and adding the results.
Page 589 - Ignorance of the law of contrast has, among drapers and manufacturers, been the subject of many disputes, which I have been happy to settle amicably, by demonstrating to the parties that they had no possible cause for litigation in the cases they submitted to me. I will relate some of these, to prevent similar disputes.
Page 696 - ... so that a low intensity upon the placard appeared satisfactory. With the diffused lighting system they were brilliantly illuminated and so effected the eye that a very intense illumination was required upon the placard. From the foregoing, the writer has drawn the following conclusions : In diffused lighting systems of the class considered, where the illumination of a working plane is one of the prime objects, a large proportion of the light is lost; that which is not lost becomes less effective...