Natural Philosophy ...

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 electric fluid electroscope employed equal experiments Fahrenheit focus force galvanic glass gravity greater heat horizontal hygrometer inch induction instrument intensity iron length lens lenses lever light magnet ment mercury metal 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 right angles ring round side south pole specific gravity spherical aberration steel substance surface telescope temperature theory thermometer thickness tion tricity tube velocity vertical voltaic weight wire zinc