Elements of Physics, Volumen2Longman, Brown, Green, and Longmans, 1846 |
Términos y frases comunes
according æther aperture atmosphere axis become bodies boiler boiling bulb caloric centre colours concave concave mirror condensed consequently convex lens crystal degree density dipping needle direction distance double refraction earth engines equal expansive force experiments Fahr fluid focal focus gases glass greater Hence horse-shoe hygrometer hygroscopic inches increased intensity inverted image iron latent heat length lenses liquid luminous magnetic influence magnifying maximum means mercury metal mirror needle north pole object observed oscillations parallel particles perpendicular phenomena piston placed plane plate polarized portion position pressure prism prismatic produced quantity radiation rays of light reflected reflecting telescopes retina right angles Second Expt solid south pole specific heat spectrum steam substances surface telescope temperature terrestrial terrestrial magnetism theory thermometer thermoscopic Third Expt transmitted transparent tube vapour velocity vessel vibrations violet waves whence white light
Pasajes populares
Página 114 - Hence it is, also, that no discordance arises between the sensations of inverted vision and those of touch, which perceives everything in its erect position ; for the images of all objects, even of our own limbs, in the retina, are equally inverted, and therefore maintain the same relative position.
Página 82 - 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...
Página 297 - It has been ascertained that the breadth of a bar magnet should be about one-twentieth of its length, and its thickness from one-fourth to one-third of its breadth. In a horse-shoe magnet, the space between the two poles ought not to be greater than the thickness of the bar of which the magnet consists. Lastly, it is necessary that both bar and horse-shoe magnets be well polished, and that their faces be as level as possible. Magnetism is readily excited in soft Iron Bars.
Página 114 - Optics ; and, if everything is seen reversed, the relative position of the objects remains unchanged. Hence it is, also, that no discordance arises between the sensations of inverted vision and those of touch, which perceives...
Página 197 - This is strikingly shown in an alloy called the " fusible metal," which is composed of 8 parts of bismuth, 5 of lead, and 3 of tin, and melts at 203° F.
Página 170 - ... generally bad radiators. If a metal surface be scratched or made rough its radiating power is greatly increased. Water in a highly polished metal pot will retain its heat much longer than in one that is black and dull. Leslie procured a cubical vessel of block tin : one side was polished, the second was made rough by scraping, the third he covered with a glass plate, and the fourth he blackened with lampblack. He then filled the vessel with boiling water, and presented the different sides in...
Página 81 - I conclude that the solar spectrum consists of three spectra of equal lengths, viz. a red spectrum, a yellow spectrum, and a blue spectrum. The primary red spectrum has its maximum of intensity about the middle of. the red 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...
Página 39 - The principal focus of a convex mirror lies as far behind the reflecting surface as in concave mirrors it lies before it.
Página 134 - 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.
Página 194 - The heat which is expended in changing a body from the solid to the liquid state, or from the liquid to the gaseous state, is called latent heat.