This is the atlas referred to in the text. The letter-press is short, and is repeated in English, French, and German. 2. “Annals of the Astronomical Observatory of Harvard College.” Vol. XXX. Observations made at the Blue Hill Meteorological Observatory. Part III. Measurement of Cloud Heights and Velocities. By H. H. Clayton and S. P. Fergusson. Part IV. Discussion of the Cloud Observations. By H. H. Clayton. This last gives a very concise account of all the different proposals which have been made for the systematic naming of clouds. 3. “Études International des Nuages.” 1896-1897. Observations et Mesures de la Suède. I., II. Publication de l’Observatoire Météorologique de l’Université Roy. d’Upsala. H. H. Hildebrandsson. An account of the Upsala observations referred to in the text. 4. _Quarterly Journal of the Royal Meteorological Society_. Helm Wind. Marriott. 1886 and 1889. The Thickness of Shower Clouds. Clayden. 1886. Methods of Cloud Measurement. Ekholm. 1888. Cirrus Formation. Clayton. 1890. Nomenclature of Clouds. Hildebrandsson. 1887. „ „ Abercromby. 1887. „ „ Wilson-Barker. 1890. „ „ Gaster. 1893. „ „ Scott. 1895. A New Instrument for Cloud Measurement. Ekholm. 1893. Calculation of Photographic Cloud Measurements. Olsson. 1894. The Motion of Clouds. Shaw. 1895. 5. Reports of the British Association. Reports of the Committee on Meteorological Photography. Clayden. 1891 to 1900. The reports for 1896 and 1900 refer mainly to the measurements described in the text. 6. “Cloudland.” Clement Ley. The work in which Mr. Ley set forth his proposed scheme. 7. “A Popular Treatise on the Winds.” Ferrel. Not a “popular” work in the usual sense, but contains lucid descriptions of the mechanics of the atmosphere. 8. There are many excellent text-books on meteorology, all of which deal more or less with the movements of the atmosphere and the formation of clouds. 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