S.
- Satellites, [80], [111], [113].
- Saturn, [85].
- Scales, or balance, [55].
- Screw, [54], [67].
- Shadow, [110], [111].
- Siderial time, [106].
- Sight, [165].
- Signs of the zodiac, [86], [93].
- Smoke, [14], [29].
- Solar microscope, [202].
- Solstice, [100], [102].
- Sound, [151].
- Space, [33].
- Specific gravity, [123].
- of air, [140].
- Spectrum, [190].
- Speaking-trumpet, [154].
- Sphere, [26].
- Springs, [130].
- Spring tides, [116].
- Square, [81], [85].
- Stars, [77], [86], [102].
- Storms, [147].
- Substance, [10].
- Summer, [76], [100].
- Sun, [71], [75], [78], [162], [182].
- Swimming, [41].
- Syphon, [132].
T.
- Tangent, [49], [73].
- Telescope, [203], [204].
- Temperate zone, [92], [101].
- Thermometer, [142].
- Tides, [114], [116].
- Time, [105], [107].
- Tone, [155].
- Torrid zone, [93], [147], [182].
- Transit, [114].
- Transparent bodies, [157].
- Treble and bass, [155].
- Tropics, [92].
V.
- Valve, [143].
- Vapour, [17], [29], [104], [129].
- Velocity, [33], [57].
- Venus, [84].
- Vesta, [84].
- Vibration, [98], [152].
- Vision, [164], [168].
- Vision, angle of, [168], [170].
- double, [171].
U.
W.