ASTRONOMY.] 



INDEX TO VOL. I. 



1247 



Water-wheel, breast and undershot com- 

 bined, 832. 

 Water-wheel (breast), comparative power, 



831. 



Water-wheel (breast), estimated power, 

 832. 

 Water-wheel (breast), where applicable, 



833. 



Water-wheel, overshot, 828. 

 Water-wheel, overshot, its best construc- 

 tion, 830. 



Water-wheel, overshot, its most advanta- 

 geous velocity, 830. 



Water-wheel, overshot, rules for calcu- 

 lating velocity, 829. 

 Water-wheel, overshot, where applicable, 



833. 



Water-wheel turbine, 834. 

 Water-wheel turbine described, 834. 

 Water-wheel turbine, estimated power, 



835. 



Water-wheel, undershot, 825. 

 Water-wheel, undershot, the greatest pos- 

 sible effect, 767. 



Water-wheels are of three kinds, 825. 

 Water-wheels, regulators for, 833. 

 Water-wheels, undershot ; their velocity 

 should not eiceed one-third that of the 

 stream, 827. 



Water-works for supplying towns, 879. 

 Watt began a new era in the mechanical 

 arts, 778. 



governor for steam-engines, 862. 

 Watt's improvements in the steam-engine, 



871. 



Watt's parallel motion, 873. 

 Watt's sun and planet wheels, 899. 

 Weaving-machinery, 783. 

 Wedge, 719, 731. 

 Wedge, a machine, 783. 

 Weighing-machines, 725. 

 Weight, 691. 

 Weight a source of mechanical force, 



817. 

 Weight source of power, 781, 837. 



Weight an element for measuring power, 



781. 



Weight and velocity are convertible, 781. 

 Weight as a measure of mechanical work, 



883. 



Weight, explanation of this term, 750. 

 Weight multiplied by the velocity repre- 

 sents horse-power, 781. 

 Weight of a body, 691. 

 Weight of a body, how it may be readily 



determined, 755. 

 Weight of bodies as a moving power, 



837. 

 Weight true or absolute is the weight in a 



vacuum, 756. 



Weight without motion, its law, 882. 

 Weights and measures, 905. 

 Weights in French and English, how to 



reduce, 905. 

 Weights preferable to springs for regular 



motion, 839. 



Weights raising machinery, 783. 

 Weir to check a stream, 833. 

 Wheel, a machine, 783. 

 Wheel and axle, 719, 727. 

 Wheel and worm, 892. 

 Wheel-barrow, the action of man by, 818. 

 Wheel, bevelled, 728, 891. 

 Wheel, Catherine, its pr.nciple applied to 



turbines, 834. 

 Wheel, elliptical, 898. 

 Wheel, Persian, for raising water, 836. 

 Wheel, sun and planet, 899. 

 Wheel, toothed, 719, 728, 887. 

 Wheel, undershot, to find the greatest 



possible effect, 767, 827. 

 Wheel-work, 887. 

 Whitelaw's turbines, 835. 

 White's pulley, 730. 

 Winch, 727. 



Winch, manual labour at the, 819. 

 Wind, computation of its power, 820. 

 Wind, its pressure proportional to the 



square of the velocity, 820. 

 Wind-power, 820. 



Wind, table of velocity of, 820. 

 Wind, when first converted into mechani- 

 cal force, 819. 

 Windlass, 727, 783. 

 Windlass, the friction of ropes or chains, 



903. 



Windmills, advantages of, 825. 

 Windmills, apparatus for regulating, 823, 



824. 

 Windmills forgiving motion to machinery, 



822. 

 Windmills, horizontal, not so effective as 



vertical, 822. 

 Windmills partially surrounded by a 



casing, 822. 



Windmills, power of, 825. 

 Windmills, self-regulating, 824. 

 Windmills, their construction, 822, et sej. 

 Windmills, velocity of, 825. 

 Wine-taster described, 775. 

 Winnowing corn by steam power, 880. 

 Wire-drawing machinery, 783. 

 Wire, the strength computed, 800. 

 Wood columns, experiments on, 801. 

 Wood, data for calculating the strength, 



797. 

 Wood, experiments as to compression, 



800. 

 Wood, how sections in drawing are 



hatched, 790. 



Wood on wood, table of friction, 902. 

 Wood-working machinery, 880. 

 Wool, machinery for preparing, 783. 

 Woollen cloth, table of friction, 902. 

 Work defined, 781. 

 Work, mechanical, defined, 882. 

 Working-drawings, what are, 790. 

 Worm and wheel, 892. 

 Wrenching force, 812. 

 Wrinkling adds to the stiffness of plates, 



S08. 

 Wurtemberg syphon, 773. 



YARD, a measure of length, 692. 

 York paving, crushing pressure, 802. 



SECTION X. ASTRONOMY. 



ABERRATION of light, 931. 



Acceleration, daily, defined, 918. 



Aldebaran, 959. 



Algol, 959. 



Altair, 960. 



Altitude and azimuth instrument, 998. 



Andromeda, 959. 



Andromeda, nebula of, 956. 



Annual equation of the moon, 937. 



Annular nebula;, 957. 



Annular solar eclipses, 982. 



Aphelion defined, 918. 



Apogee defined, 918. 



Apparent magnitude of the itars, 950. 



Apsides, line of, 923. 



Apsides of the moon, 936. 



Aquila, 960. 



Arc of meridian, determining the length 



of an, 921. 

 Arcturns, 959, 960. 

 Artificial day, 919. 

 Ascension, right, defined, 917. 

 Asteroids, 946. 



Asteroids, discovery of the, 917. 

 Asteroids, distance of the, 947. 

 Asteroid*, telescopic appearance of the, 



947. 



Astronomical day, 919. 

 Astronomical instruments, 989, ft teg. 

 Astronomical telescopes (see also Index 



p. 1219), 991. 

 Astronomy, cometary, 960. 

 Astronomy, history and definitions of, 913. 



Astronomy, planetary, 940. 

 Astronomy, practical, 989. 

 Astronomy, stellar, 950. 

 Atmosphere of Jupiter, 947. 

 Atmosphere of Mars, 946. 

 Atmosphere of Venus, 946. 

 Atmosphere of the earth, 924. 

 Atmosphere, solar, 934. 

 Atmosphere, tides of the, 989. 

 Axis of the earth defined, 916. 

 Axis of the earth, inclination of the, 923. 

 Axis of the earth, nutation of the, 933. 

 Azimuth and altitude instrument, 998. 

 Azimuthal errors, determination of, 1005. 



BAILY'S beads seen during a solar eclipse, 



984. 



Bear, great, constellation of the, 959. 

 Bellatrix, 959. 

 Belts of Jupiter, 947. 

 Betelgeux, 959. 

 Biela's comet, 962. 

 Bootes, 959. 

 Brorsen's comet, 963. 



CANIS major, 959. 



('mis minor, 959. 



Cassiopeia, 959. 



Castor and Pollux, 959. 



Catalogues of stars, 951. 



Centrifugal force of the rotation of the 



earth, 988. 

 Ceres (see Asteroids), 946. 



Circle, the repeating, 994. 

 Circles in astronomy, 916. 

 Circumference, equatorial, of the earth, 



922. 



Clock-errors, 1016. 

 Clock-errors of observers, 1001. 

 Cluster of Hercules, 955. 

 Collimation, errors of, formulae for. 1005. 

 Collimation, errors in observance of, 1002. 

 Collimation, formula for determining, 



1013. 

 Collimation, tables illustrating, observed 



and corrected, 1003. 

 Colure, equinoctial, defined, 923. 

 Colure, solstitial, defined, 923. 

 Colures defined, 917. 

 Cometary nebulee, 957. 

 Comet, Gambart's or Biela's, 963. 

 Comet, Halley's, 961. 

 Comets, elements of, 961. 

 Comets, history and notes on various, 



96.; 972. 



Comets, light, &c., of, 962. 

 Comets, low gravity of, 988. 

 Comets, nature of, 963. 

 Comets, notes on all observed since 371 



B.C., 964972. 

 Comets, periodicity of, 961. 

 Comets, physical appearance of, 961. 

 Comets, recent, 972. 

 Comets, tables of the orbits, elements of, 



observed during the last two thousand 



years, 10311034. 



