Stitntifit�mtrican + though kept in a close room, travlils more than pheric vapor by stretching' longitudinally. haIr an inch Pilr week. In order to ascertain Their comparative increase is seen in the order the relative absorbing powers of difl"iJrent woods, just given j sprupe gaining a quarter of an inch �--(For the Sclentillc American.) , Dendrology. -I procured similar slips of the spruce, oak, elm, over butternut. By this hygrometer it may be pine, cherry, chesnut, ash, hemlock, bass, and

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... roved that the amount of moisture in the air butternut, which when baked were exactly increases from sunrise till 9 A. M. j decreases eight inches in length. These being fastened I till 4 P. M., and again increases till () P. M.