File:The geology of New Hampshire. A report comprising the results of explorations ordered by the legislature (1874) (14753516126).jpg

Identifier: cu31924003939885 (find matches)
Title: The geology of New Hampshire. A report comprising the results of explorations ordered by the legislature
Year: 1874 (1870s)
Authors: New Hampshire. State geologist (1868-1878) Hitchcock, Charles H. (Charles Henry), 1836-1919
Subjects: Geology Rivers Insects Botany Fragilariaceae Drift Mineralogy Physical geography
Publisher: Concord, E.A. Jenks, state printer
Contributing Library: Cornell University Library
Digitizing Sponsor: MSN

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per year since the country has been cul-tivated,—and there has been a great increase of vegetation on account ofirrigation,—is an important example, as showing the effect of the increaseof vegetation.* The preservation of the vegetation on our mountains is of greatimportance, not only in modifying the distribution of rain, but also inmoderating the extremes of cold in winter. Our mountains, especially the higher summits, except where it has beendestroyed by fire, are covered to a considerable depth by peat formedchiefly from moss and lichens. Now it has been found by experimentthat peat moss can absorb more than twice its own weight of water, dryclay nearly its own weight, dry earth, or garden mould, more than half itsown weight, and dry sand a little more than a third of its own weight.With equal times of drying, under the same circumstances, peat moss losttwo thirds of all the water it contained, clay and earth more than three * Monthly Reports of the Department of Agriculture.
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CLIMATOLOGY OF NEW HAMPSHIRE. 125 fourths, and sand more than nine tenths. Farmers can determine thecapacity that different soils have for retaining moisture, by taking twoboxes, filling each with a different kind of soil, and pouring an equalquantity of water on each, and then suspending each of the boxes at theend of a balance, so adjusted that the bar shall be horizontal. Then, ifthe soils are unequal in their capacity for retaining moisture, one box willsoon rise above the level of the other. This experiment was first per-formed by D. Milne Home. When a mountain has been denuded of itsforests and vegetable mould, the rain that falls upon it flows immediatelyinto the streams, and is carried to the ocean; then, before another rain,the streams are dried up, the rivers are greatly contracted, and the nextrain causes a freshet;—so we have a succession of drouths and floods.On the other hand, vegetable mould retains the moisture, and it is grad-ually evaporated, a high relative humidicu31924003939885

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