Part 57

Wheels invented to test intensity of sound, 132, 133.

Wheat, range of its cultivation, 250.

Wheatstone, Professor, experiments in acoustics of, 132; musical instruments invented by, 143; paper on musical vibrations read by, 145; experiments on sounding boards of, 150; experiments on sound reinforced by resonance, 151; instrument measuring velocities of electricity and light invented by, 202; spectrum of an electric spark observed, 289; speed of electricity measured, 289, 290; experiments on the spectrum of Voltaic flame, 303.

Willis, Mr., articulating machine invented by, 151; investigations of, into the mechanism of the larynx, 152.

Winds, trade, 122, 123; monsoons, 124; extra-tropical, in the North Atlantic, _ib._; currents above the trade winds, 124, 125; phenomena of rotatory motion, 125; hurricanes, 125, 128; agency of, influencing temperature, 244, 245.

Wines, range of cultivation of the best, 250.

Winter, atmospheric electricity in, 291.

——, mean temperature of, varying in the same latitude, 246, 247.

Wolf, Professor, periods of variation in solar heat computed by, 225.

Wollaston, Dr., experiments of, on sensitiveness to sound, quotation from, 132; experiment of, to show the effect of variable media on refraction, 156; discovery of rayless lines in the solar spectrum, 162; observations of, on the chemical properties of the solar spectrum, 203, 209; magnetic rotation suggested by, 313; light emitted by the heavenly bodies calculated, 404.

Xi Ursæ Majoris, periodic time of, 398; velocity of the revolving star, 400.

Year, a, in Jupiter and Saturn, 66; tropical change in its length, 80; length of the sidereal, _ib._; period of the mean, 83; estimation of the Egyptian, 85; first of our era, 86; length of the, affected by a comet’s passage, 359.

Young, Dr., his calculation of the possible compression of solids, 78; date of a horoscope determined by, 89; density of a liquid column estimated by, 114; exception adduced by, to a general law in acoustics, 137; his theory of the pleasures of harmony, 142; undulatory theory established by, 169; data used by, to test his theory of light, 175; illustration of, proving sound and heat kindred forces, 280, 281.

Zeta Cancri, a triple star, 395; periodic time of, 398; revolution, 400; colours, 401.

Zeta Herculis, periodic time, eclipse of, 398; light, 402.

Zinc, seleniate of, effect of temperature on its crystals, 107; sulphate of, its crystals boiled in alcohol, 108.

——, electricity communicated to plates of, 220.

Zodiac, the, signs of, change in their positions, 80.

Zone of constant temperature in the atmosphere, 119; laws of storms in the temperate and torrid, 127, 128; of spots on the sun’s surface, its breadth, 224; of constant temperature below the earth’s crust, 228; comparative unequal distribution of land in temperate and torrid, 244; of fixed stars, 385; of stars nearest the sun, 390; nebulous, 416; of nebulous patches, 417; of meteoric nebulæ, 423.

Zones of instability of planetary orbits, 21.

—— of temperature in the ocean, 101.

—— of vegetation on the Peak of Teneriffe, 250.

Zoophytes, specific distribution of, 254.

THE END.

LONDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET, AND CHARING CROSS.

These correspond to No. 1, 6, and 7 of Faraday’s plate in his 29th Series of Experimental Researches in Electricity.

Footnotes

Footnote 1:

The mean distance of the earth from the sun is 95,000,000 miles, but to avoid the inconvenience of large numbers, it is assumed to be the unit of distance; hence the mean distance of Mars is 1·52369, or 1·5 nearly, that of the earth being = 1.

Footnote 2:

The obliquity given in the text is for the year 1858.

Footnote 3:

Sir John Herschel remarks that there are just as many thousands of feet in a degree of the meridian in our latitude as there are days in the year, viz. 365,000.

The Greenwich Observatory is in N. lat. 51° 28ʹ40ʺ.

Footnote 4:

Or more correctly 3422ʺ·325 and 238,793 miles, as deduced from Mr. Adams’ more accurate calculations.

Footnote 5:

Neptune was discovered in the year 1846.

Footnote 6:

The satellites of the two great planets on the farthest verge of the solar system form a singular exception to this law.

Footnote 7:

See the chapter on the Tides and Currents in the ‘Physical Geography,’ by the author, 4th edition.

Footnote 8:

Sir John Herschel on Meteorology.

Footnote 9:

Bakerian Lecture, by Michael Faraday, Esq. Phil. Trans. 1857.

Footnote 10:

See page 104.

Footnote 11:

M. Marbach of Breslau.

Footnote 12:

‘Meteorology,’ by Sir J. Herschel.

Footnote 13:

This theory of heat and motion originated with Mr. Joule, of Manchester, who has maintained it with the greatest talent, both by experiment and analysis; and it has had an able advocate in Professor W. Thomson, of Glasgow.

Footnote 14:

To this remarkable man the world is indebted for the locomotive railway system, which is rapidly advancing the civilization of mankind. Britain may well be proud of its working classes, which can produce such men; and Mr. George Stephenson is not the only one; there are many others; but no man has ever had greater influence by his labours and discoveries on human affairs.

Footnote 15:

‘Correlation of the Physical Forces, by W. R. Grove, Esq.,’ one of the most remarkable and talented works that has appeared, to which the author with pleasure acknowledges her obligations.

Footnote 16:

“Eripuit fulmen Cœlo, sceptrumque tyrannis,” is the inscription on a medal struck in honour of Franklin.

Footnote 17:

Faraday.

Footnote 18:

Professor Matteucci still expresses doubts on this subject, but has not yet finished his experiments.

Footnote 19:

Babbage.

Footnote 20:

Phil. Mag. for May 1858.

Transcriber's Notes

Some corrections were made to the original text. In particular, punctuation was corrected without further note. Inconsistent spelling and hyphenation was retained unless noted otherwise. There were two Notes 189 in the original; this was retained as printed. Spelling of Index entries was changed to reflect the body text where inconsistencies were found. Index page numbers were corrected where errors were found. Further corrections are noted below:

p. 50 0·005·1449 -> 0·0051449 p. 61 24,000 -> 240,000 p. 62 M. Leverrier -> M. Le Verrier p. 84 in mean solar day -> in a mean solar day p. 96 syzigies -> syzygies p. 115 arrising -> arising p. 120 Herchel -> Herschel p. 123 generally know -> generally known p. 159 Fraunhoffer’s -> Fraunhofer’s p. 168 contaary -> contrary p. 214 oxyde -> oxide p. 216 aperature -> aperture p. 296 M Niepce -> M. Niepcé p. 306 torrecelian -> Torricellian p. 307 potass -> potash p. 350 de Roux -> le Roux p. 423 Β -> β p. 447 areal -> aërial p. 456 perigree -> perigee p. 471 108° -> 180° p. 478 Meissier -> Messier