A Plain Elementary and Practical System of Natural Experimental Philosophy: Including Astronomy and Chronology

altitude angle of incidence angle of refraction aphelion appear apsis atmosphere attraction axis called cause central force circle colour comets concave concave lens converge convex lens degree denser medium descend diameter direction diverge earth ecliptic elastic electricity ellipsis equal equator eye-glass fall fluid focal distance focus glass globe greater greatest half heat Hence hole horizon increased inversely Jupiter latitude length less mean mercury meridian mirror moon moon's motion move nearer node object observed octave orbit parabola parallax parallel particles pass perpendicular plane Plate pole pressure produced projectile proportional quadrature quantity of matter radiant point radius rays of light reflected reflexion retina revolution revolving right ascension round side sine solar sound space specific gravity square root star star's string sun's superior planets supposed surface syzygies tance tangent telescope thereby tion tube velocity vessel vibrations weight whole