. Desert botanical laboratory of the Carnegie institution. Desert Botanical Laboratory of the Carnegie Institution; Botanical laboratories. 44 DESERT BOTANICAL LABORATORY 11 per cent greater than at the sea level in a humid atmosphere, and that the intensity is 26 per cent greater at an altitude of 15,600 feet, on the summit of Mont Blanc, than at sea level. It is to be seen by refer- ence to the curve of humidity that the amount of moisture in the air in the locality under discussion is at times extremely small, which would further intensify the insolation. It would be entirely safe therefore
. Desert botanical laboratory of the Carnegie institution. Desert Botanical Laboratory of the Carnegie Institution; Botanical laboratories. 44 DESERT BOTANICAL LABORATORY 11 per cent greater than at the sea level in a humid atmosphere, and that the intensity is 26 per cent greater at an altitude of 15,600 feet, on the summit of Mont Blanc, than at sea level. It is to be seen by refer- ence to the curve of humidity that the amount of moisture in the air in the locality under discussion is at times extremely small, which would further intensify the insolation. It would be entirely safe therefore in a comparison of this summit with that of Mont Blanc to say that the. Fig. 4. Meteorological data from San Francisco mountain, Arizona, Aug. 8 to Aug. 19, 1898. The upper curve, traced from the hygroscopic record shows variations in relative humidity. The lower curve shows the corresponding air temperature in the shade. The instruments were in the shelter shown in Plate XXIX. intensity of the sun's rays is at least 25 per cent, greater than at sea level and about 12 per cent, more than on the plain below, which by its altitude and other conditions would in turn be about 12 or 13 percent, greater than at sea level. The species of plants inhabiting this and all alpine situations are al- most altogether perennials, passing the unfavorable season in the form of a fleshy or woody rootstock. The aerial shoots are generally pros- trate and lie close to the ground, a device generally conceded to be due to the thermotropism of the plant whereby it receives all possible advantage of the higher average temperature of the soil than of the air. So far as the structural features of alpine plants are concerned it. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Coville, Frederick V. (Frederick Vernon), 1867-1937; MacDou
Size: 1972px × 1267px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthormacdouga, bookcentury1900, bookdecade1900, bookyear1903
