Library of Useful Knowledge: Natural philosophy, Volume 2

achromatic acid action aperture appear ascer attraction axis ball battery body brass centre centre of gravity circle colours compass concave conductor convex convex lens copper cylinder degree diameter direction distance earth effect elec electric current electroscope employed equal experiments Fahrenheit fixed fluid focus force galvanic glass gravity greater heat horizontal hygrometer inch increased induction instrument intensity iron length lens lenses lever light magnet ment mercury meridian metal microscope motion move needle Newton north pole object object-glass obliquely observed opposite parallel particles passing perpendicular phenomena piece placed plane plate polarity portion position prism produced proportion pyrometer quantity rays rection reflected refraction refrangible rendered repulsion retina ring round side south pole spherical aberration steel substance surface telescope temperature theory thermometer thickness tion tricity tube velocity vertical voltaic weight wire zinc