INDEX
Abercromby, [10]
Aitken, [3], [91]
Altitude of clouds, [19], [149]
—— of rain-clouds, [76]
Alto clouds, [59], [159]
Alto-cumulus communis, [161]
—— castellatus, [66], [160]
—— glomeratus, [67], [161]
—— informis, [64], [160]
—— nebulosus, [65], [160]
—— stratiformis, [65], [161]
Alto-strato-cumulus, [70], [160]
Alto-stratus maculosus, [68], [160]
Ascent of vapour, [124]
Atlas, International, [11]
Band cirrus, [41]
Bidwell, Shelford, [92]
Black mirror, [14], [173]
Blue Hill, [20], [138]
Cameras, [140], [171]
Change cirrus, [37]
—— of velocity, [35]
Cirriform top of thunder-cloud, [110]
Cirro-cumulus, [45], [159]
—— nebulosus, [52], [159]
Cirro-filum, [33], [156]
Cirro-macula, [53], [159]
Cirro-nebula, [26], [27], [155]
Cirro-stratus, [45], [157]
—— communis, [47], [158]
Cirro-stratus cumulosus, [48], [158]
—— nebulosus, [45], [158]
—— vittatus, [158]
Cirro-velum, [24]
Cirrus, [21], [155]
—— altitudes, [30], [149]
—— communis, [40], [157]
—— caudatus, [34], [156]
—— excelsus, [31], [156]
—— inconstans, [37], [157]
—— nebulosus, [36], [156]
—— ripples, [51]
—— ventosus, [32], [156]
—— vittatus, [41], [156]
Cloud altitudes, [149]
—— nuclei, [3]
—— photography, [17], [165]
Condensation, [93]
Cooling by contact, [89]
—— by expansion, [92]
—— by mixture, [90]
—— by radiation, [88]
Development, [175]
Differential currents, [133]
Diffraction, [63]
Dimensions of clouds, [112]
Dry fog, [73]
Equilibrium, stable and unstable, [106]
Exeter measurements, [137]
Exposure, [167]
Fall cloud, [81], [88]
False cirrus, [110]
Fog particles, [60]
Fracto, [164]
Gravitation, [4]
Great waves, [129]
Halos, [21], [22], [23]
Heat cumulus, [85]
—— thunderstorms, [107]
Hildebrandsson, [10]
Hoar frost, [60]
Howard, Luke, [9], [10]
Intensification, [177]
Interconvection, [125]
International Code, [11]
—— Committee, [10]
—— System, [12], [71]
Ions as nuclei, [92]
Irregularities of ground, [39]
Kepler, [4]
Kew, [138]
Ley, Clement, [24], [34], [55]
Lightning, [114]
Lower clouds, [71]
Mammato-cumulus, [99]
Meteorological Conference, [9]
Methods of computing altitudes, [143]
Munich, [9]
Newton, [4]
Nimbus, [74], [163]
Nuclei, [92]
Photographic methods, [17], [165]
Rain-clouds, altitude, [76]
——, thickness, [81]
Rate of fall of temperature, [94]
Sandstorms, [117]
Saturation, [87]
Scotch mist, [73]
Slow plates, [167]
Spread of condensation, [57]
Stable equilibrium, [106]
Strato-cumulus, [77]
Stratus, [72], [161]
—— communis, [77], [161]
—— lenticularis, [80], [98], [162]
—— maculosus, [78], [162]
—— radius, [79], [162]
Subsidence of cloud top, [111]
Surfusion, [61]
Swing stand, [171]
Turreted cloud, [66]
Tycho Brahe, [4]
Types, [8]
Umbra and penumbra, [29]
Undatus, [164]
Unsaturated cloud, [101]
Upsala, [10], [138]
Wave clouds, [47], [119], [133]
Wilson, C. T. R., [92]
THE END
PRINTED BY WILLIAM CLOWES AND SONS, LIMITED, LONDON AND BECCLES.
FOOTNOTES:
[1] See reference No. 2 on p. [181].
[2] The telescope with which these observations have been made is a 6·8-inch refractor equatorially mounted.
[3] Ferricyanide of potassium and hyposulphite of soda.
[4] From the declination of the sun corrected for variation and from the known latitude, the meridian zenith distance is calculated.
From the Greenwich time, the longitude, and the equation of time, the hour angle is obtained.
Now, if H be the hour angle, D the reduced declination, and M the meridian zenith distance, the sun’s altitude may be calculated by the formula—
log versin H + L cos lat. + L cos D-20 = log n,
where n is a natural number, and
n + vers M = covers alt.
Again, to find the azimuth—
vers sup. (lat. + alt.)-vers polar dist. = m,
where m is another natural number, and
log m + L sec. lat. + L sec. alt.-20 = log vers azim.,
reckoned from the south.
Hence the position of the sun is ascertained for both negatives.
By actual measurements on the plates and reference to a previously constructed scale the position of the cloud as seen from each camera is next determined, and the angle subtended by the base line at a point X vertically beneath the cloud is calculated. If A and B are the stations, and a and b the angles from them respectively, the distance AX is given thus—
log AX = L sin b-L sin AXB + log AB,
and the height h of the cloud above X is given by—
log h = log AX + L tan alt.-10.
Transcriber’s Note
Variations in hyphenation (i.e. thunderstorm and thunder-storm) have been retained. The following apparent typographical errors were corrected:
Page [171], “focussed” changed to “focused.” (it should be focused on the horizon)
Page [173], “aperature” changed to “aperture.” (the lens with its large aperture)