Page:Popular Science Monthly Volume 41.djvu/154

144 on which bellows are made to play. In due time the tray is removed by means of pieces of bamboo and the metal is poured into sand molds. The entire district is said to be rich in copper, and masses of malachite are frequently found in the Ludima.

has been shown by Mr. Aitken that the presence of dust, affording a free surface on which vapor may condense, is essential to the production of fog. The specific action of the dust varies considerably according to its composition and to the size and abundance of the particles present. Sulphur burned in the air is an active fog-producer; so are salt and hygroscopic bodies generally. Non-hygroscopic bodies also produce it, especially if they are good radiators of heat. The exceedingly minute amount of matter capable of inducing fog is a noticeable feature in the investigation. The condensation of moisture upon dust offers an effective process for removing all kinds of impurities from the air, for the floaticles are weighted by the moisture settling upon them.

 

Author:Andrew Crombie Ramsay an eminent British geologist of the last generation, died December 9, 1891, at the age of about seventy-six years. He was first brought into notice by a geological model of the isle of Arran, constructed from his own survey, which he exhibited at the Glasgow meeting of the British Association in 1840. He was afterward appointed, through the influence of Sir Roderick I. Murchison, on the Geological Survey, with which he labored in Wales. His monograph on the geology of North Wales presented the results of his labors in this field. Between 1848 and 1851 he was Professor of Geology in University College, London; in 1851 he was chosen one of the professors of the newly founded School of Mines. As a geological lecturer, the Athenæum says, he probably never had an equal. He retired from active life about ten years ago.

a well-known German geologist, died in Berlin in December, 1891, aged eighty-one years. He was the traveling companion of Leopold von Buch in his scientific expedition; succeeded him as a member of the Berlin Academy of Sciences; and issued, in conjunction with Roth and Eck, a collected edition of his works.

an English naturalist, died February 27th, in the sixty-eighth year of his age. In 1848 he went with Alfred Russel Wallace on a natural-history exploration of the Amazons, where he remained for several years after Mr. Wallace returned home. On his return he published a paper on "mimetic resemblance" in animals, recording some of the first observations made on that subject. After 1864 he was Assistant Secretary of the Royal Geographical Society, and editor of its journal and proceedings. He was the author of the books, The Naturalist on the River Amazon, Illustrated Travels, The German Arctic Expedition of 1869–'70, and Central America, West Indies, and South America.

death is announced from St. Petersburg of the African traveler and naturalist, Dr. Wilhelm Junker. He made several valuable explorations in central Africa, in the country west of the Nile, and between the Bahr-el-Gazel and the equator; among the Niam Niams; and of the course of the river Welle.

of Columbia College, died suddenly, February 7th, in the seventy-third year of his age. Besides several text-books in mathematics, he published The Elements of Mechanics in 1859, an edition of Ganot's Physics in 1860, and was joint editor with Charles Davies of the Mathematical Dictionary and Cyclopædia of the Mathematical Sciences.

Professor of Geology and Mineralogy in Cornell University, who died last November, was only twenty-nine years old; yet he had, after taking his degree at the Rensselaer Polytechnic Institute, studied three years at Göttingen, acted as assistant to Dr. Klein in Berlin, served as curator of the mineralogical and geological collection of Pratt Institute, participated in an important part of the State survey of Arkansas, collecting minerals for a complete report on the mineralogy and petrography of the State, and published several important papers and two (including one in press) large works on subjects within the sphere of his specialty.

Curator of the Harvard Herbarium, died in Cambridge, Mass., March 9th, in the seventy-second year of his age. He was graduated from Yale College in 1847; served as a tutor in Iowa University; studied medicine and practiced it for two years; was engaged in business in Alabama, where he also paid some attention to botany; afterward co-operated in literary work with Dr. Henry Barnard at Hartford, Conn.; was botanist of the surveying expedition of the fortieth parallel, or Clarence King Expedition; and after 1870 passed most of his time at Cambridge in the study of the North American flora. He published an Index to North American Botany; in conjunction with Prof. Gray and Prof. Brewer, the Botany of California; completed the work of Lesquereux and James on American Mosses; and after Prof. Gray's death became curator of the university herbarium, and continued the editing of the Synoptical Flora of North America. He was botanical editor of the earlier volumes of the Century Dictionary, and published many papers in the Proceedings of the American Academy of Arts and Sciences. 