. Popular science monthly. Fig. 3. Showing epi-cotyl of seedling burst-ing through the Fig. 4. Showing young fronds of ostrich ferns (Onoclea Struthiopteris L.) rupturing concrete. The fronds which push themselves up through the concrete arenecessarily more backward in unfolding than the unobstructed ones,although as a rule it requires only a week or ten days for them to breakthrough. It required two years for one group of fronds to comethrough, though, as was evident from the constant upheaval of a partof the concrete one spring; but the next spring they succeeded in theirattempt. The
. Popular science monthly. Fig. 3. Showing epi-cotyl of seedling burst-ing through the Fig. 4. Showing young fronds of ostrich ferns (Onoclea Struthiopteris L.) rupturing concrete. The fronds which push themselves up through the concrete arenecessarily more backward in unfolding than the unobstructed ones,although as a rule it requires only a week or ten days for them to breakthrough. It required two years for one group of fronds to comethrough, though, as was evident from the constant upheaval of a partof the concrete one spring; but the next spring they succeeded in theirattempt. The ease with which this breaking through is accomplishedand the freedom of the ferns from scars and injuries are remarkable 234 THE POPULAR SCIENCE MONTHLY when the solidity of the concrete and the force needed to rupture it aretaken into consideration. Being interested in this phenomenon, we endeavored to learn ap-proximately the power required by the ferns to rupture the the experiment, some of the soil underneath was first excavated and alever arranged in such a way that force
Size: 2630px × 950px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookd, booksubjectscience, booksubjecttechnology
