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Pagina 90 - Thus in the red space, there is more red than is necessary to make white light with the small portions of yellow and blue which exist there ; in the yellow space, there is more yellow than is necessary to make white light with...
Pagina 120 - Without stopping to prove the principle, we may say that the magnifying power is simply equal to the quotient obtained by dividing the focal length of the object-glass by that of the eye-lens. It is to be noted, however, that a magnifying power of unity is sometimes spoken of as no magnifying power at all, since the image appears of the same size as the object.
Pagina 90 - Y equal to 3 + 2 + 1, equal to 6 parts of white mixed with 7 parts of yellow ; that is, the compound tint at Y will be a bright yellow without any trace of red or blue.
Pagina 90 - ... at any point mixed with white light. In the red space there is more red than is necessary to make white light with the small portions of yellow and blue which exist there; in the yellow space there is more yellow than is necessary to make white light with the red and blue ; and in the part of the blue space which appears violet there is more red than yellow, and hence the excess of red forms a violet with the blue.
Pagina 90 - ... space in the solar spectrum, the primary yellow spectrum has its maximum in the middle of the yellow space, and the primary blue spectrum has its maximum between the blue and the indigo space. The two minima of each of the three primary spectra coincide at the two extremities of the solar spectrum. From this view of the constitution of the solar spectrum we may draw the following conclusions : — 1. Red, yellow, and blue light exist at every point of the solar spectrum. 2. As a certain portion...
Pagina 136 - Ibs. of water one. degree in temperature. The air has here been heated under a constant pressure, and we have learned, that the quantity of heat necessary to raise the temperature of a gas under constant pressure a certain number of degrees, is to that required to raise the gas to the same temperature, when its volume is kept constant, in the proportion of 1-42 : 1 ; hence we have the statement — . . - ib».
Pagina 116 - This is effected by placing between the lens and its principal focus, a plane mirror inclined at an angle of 45° to the axis of the lens.
Pagina 140 - ... contact with a liquid. Nearly all the crystallized salts possess this property. If a mixture be made of one of these salts with snow, or with some other liquid, the action of these substances on each other will convert one or both of them into liquids, one portion of their free caloric being consumed in effecting this change, as also part of the heat of the vessels containing the mixture. The consequence is, that the greater the degree of cold generated during the liquefaction of the mixture,...