Gravitation

Citation: Piersol, Paul Du Chaillu. Gravitation. Senior thesis, Kansas State Agricultural College, 1900.Morse Department of Special CollectionsIntroduction: The real significance of Newton’s discovery of universal gravitation is fully appreciated by but few. To a certain degree, all men are acquainted with it, for it is the force which gives weight to a body or causes it to fall toward the center of the earth. But it goes still farther, determining the position of the planetary bodies, and holding them in their orbits. A large number of Philosophers before Newton were aware of the motion of terrestrial bodies, and contributed something that aided in the discovery of this law. Of these we will mention but one; Galileo, for it was by looking from the heights of Galileo’s discovery that Newton was enabled to discover the great law which he did. Galileo was born at Pisa, Italy, Feb. 14, 1564. He early showed a fondness for mathematics, and at the age of twenty was a distinguished geometrician. Five years later, he was appointed Professor of Mathematics at Pisa. It was here, while seated in a church that he noticed the slow and uniform swinging of a lamp, and inferred that this principle might be used as a measure of time. This idea he carried out fifty years later. He wrote many excellent treatises on science, and constructed many machines of public utility for the state. Among some of his inventions were the thermometer, the proportional compass, and the microscope. He was the founder of Experimental Science, and first formulated the principle of virtual velocities. He investigated the true laws of motion, and by experiment, demonstrated that gravity acts on all bodies alike, and that bodies of unequal weights will fall through the same space in equal times

Indirect evidence for the genetic determination of short stature in African Pygmies

Central African Pygmy populations are known to be the shortest human populations worldwide. Many evolutionary hypotheses have been proposed to explain this short stature: adaptation to food limitations, climate, forest density, or high mortality rates. However, such hypotheses are difficult to test given the lack of long‐term surveys and demographic data. Whether the short stature observed nowadays in African Pygmy populations as compared to their Non‐Pygmy neighbors is determined by genetic factors remains widely unknown. Here, we study a uniquely large new anthropometrical dataset comprising more than 1,000 individuals from 10 Central African Pygmy and neighboring Non‐Pygmy populations, categorized as such based on cultural criteria rather than height. We show that climate, or forest density may not play a major role in the difference in adult stature between existing Pygmies and Non‐Pygmies, without ruling out the hypothesis that such factors played an important evolutionary role in the past. Furthermore, we analyzed the relationship between stature and neutral genetic variation in a subset of 213 individuals and found that the Pygmy individuals' stature was significantly positively correlated with levels of genetic similarity with the Non‐Pygmy gene‐pool for both men and women. Overall, we show that a Pygmy individual exhibiting a high level of genetic admixture with the neighboring Non‐Pygmies is likely to be taller. These results show for the first time that the major morphological difference in stature found between Central African Pygmy and Non‐Pygmy populations is likely determined by genetic factors. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86961/1/21512_ftp.pd

Im Lande der Mitternachts-Sonne: Sommer- und Winterreisen durch Norwegen und Schweden, Lappland und Nord-Finnland - 1

Lisäpainokset: 2. p. 1885

The land of the midnight sun: summer and winter journeys through Sweden, Norway, Lapland and Northern Finland - 1

Lisäpainokset: 3. p. London 1882, 4. p. London 1888