# Popular Science Monthly/Volume 86/January 1915/The Progress of Science

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Huston Hall, the Students' Clubhouse at the University of Pennsylvania, the Headquarters of the American Association for the Advancement of Science.
THE PHILADELPHIA MEETING OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE
The American Association for the Advancement of Science and the national scientific societies affiliated with it meet at the University of Pennsylvania, Philadelphia, during the week beginning on December 27. In view of the scientific attractions of Philadelphia and its central situation for those living on the Atlantic seaboard, with convenient access for those living further west, the meeting is sure to be of outstanding importance. This has been the case with the previous Philadelphia meetings. The association was organized there in 1848. After an interval of 36 years the second Philadelphia meeting had a registration of 1,261, the largest up to that time and until very recently. Like the first meeting it marked an epoch in scientific organization in America. Until 1882 there had been only two sections of the association, one for the exact sciences and one for the natural sciences. But the advance and specialization of science led to the division of the association into sections and the establishment of national societies for the different sciences. The American Society of Naturalists was established in 1883 and as special societies were organized in the natural sciences they met with it in the Christmas holidays. National societies in the physical sciences were also formed and held separate meetings. The parent association was thus somewhat weakened, and the summer meetings attracted an attendance of only about 300.
The situation was met by the establishment of convocation week and the affiliation of the national societies for special sciences with the association. The association has aimed to serve as a center of coordination for the special sciences and the special societies, and to keep scientific men in touch with the larger public, leaving the special programs of technical papers to the separate societies The third Philadelphia meeting and at the same time the third of the convocation week meetings held in the Christmas holidays of 1904 had a registration of 890, but the registration of members of the association no longer represents the magnitude of the meetings, as it includes only a part of those attending the sessions of the special societies. When the association was organized in 1848 its membership was 461, at the second Philadelphia meeting it had increased to 2,000, at the third to 4,000 and it is now after ten years over 8,000.
list of vice-presidential addresses, which is as follows:
Vice-president Alfred D. Cole, before the Section of Physics: "Recent Evidence for the Existence of the Nucleus Atom."
Vice-president Carl L. Alsberg, before the Section of Chemistry: "Fermentation."
Vice-president O. P. Hood, before the Section of Engineering: "Safety Engineering."
Vice-president Joseph S. Diller, before the Section of Geology and Geography: "The Relief of our Pacific Coast."
Vice-president Alfred G. Mayer, before the Section of Zoology: "The Research Work of the Tortugas Laboratory of the Carnegie Institution of Washington."
Vice-president Henry C. Cowles, before the Section of Botany: "The Economic Trend of Botany."
Vice-president Judson G. Wall, before the Section of Social and Economic Science: "Social and Economic Value of Industrial Museums."
Vice-president Theodore Hough, before the Section of Physiology and Experimental Medicine: "The Classification of Nervous Reactions."
Vice-president P. P. Claxton, before the Section of Education: "The American Rural School."
Perhaps the most notable event of the meeting will be the organization of the new section of agriculture, before which Vice-president L. H. Bailey will give the address noted above, and there will be a symposium on the field of rural economies. But each section will hold meetings of general interest.
As attractive as the programs will be the place of meeting. The buildings of the University of Pennsylvania afford admirable accommodations for all sections of the association and the separate societies, while in themselves affording much of interest to scientific visitors. Houston Hall, which was the first club house for students on a large scale to be established at a university, offers excellent headquarters, whore scientific men may meet and where committee meetings may be held. One or two of the societies will meet at the Academy of Natural Sciences, whose fine new building has recently been erected. From the time of Benjamin Franklin, Philadelphia and its institutions have been among the leading educational and scientific centers of the country. It was long our chief city for medical education and research, occupying somewhat the place in science that Boston filled in letters. The recent history of chemistry in America, by Dr. Edgar F. Smith, provost of the university and chairman of the local committee for the approaching meeting, indicates the city's leadership in that science. Other scientific
centers have overtaken Philadelphia, and the University of Pennsylvania has suffered from inadequate endowment. But in recent years the growth of the university has been remarkable, and, while it may be difficult for Philadelphia to rival New York and Washington, it will surely make contributions to science commensurate with its wealth and population
THE PROGRESS IN PHOTOGRAPHY
The history of photography is well illustrated by a series of cameras, plates, and prints exhibited in the U. S. National Museum. This collection of photographic apparatus and photographs, said to be the most complete in the world, has been collected and classified by Mr. T. W. Smillie, photographer of the museum for the past forty-five years. Work of nearly all the early inventors is to be seen, and what is said to be the first American camera, that made on Daguerre's specifications for Dr. S. F. B. Moore, in 1839.
The earliest camera, the camera obscura, used by Euclid in 300 B.C., was later improved upon by Bacon and others in the thirteenth century, and further improved by Porta in the sixteenth century. It is said that the action of light on fused silver chloride was used to make a photograph of the solar-spectrum by Scheele in 1777.
Unfortunately there was then no method known for fixing the prints, and in consequence only imitations of this method are to be seen in the museum collection. Thomas Wedgwood experimented along this same line in 3 802, and prepared a paper on the subject.
The first successful inquirer to secure permanent pictures through the influence of the sun 's rays, seems to have been Nicephore Niepce, who in 1824 effected the process of heliography by the use of a varnish made of asphaltum, or bitumen of Judea, applied to a highly polished metal plate or a glass plate, and developed by essential oil of lavender and white ​petroleum. The plate was exposed for several hours, the image etched, and then prints were made as from an ordinary etching. The museum collection includes one of the first permanent photographs printed from a light etched plate by the heliographic process. This print is from Niepce's plate made-in 1824.
There are also several fine examples of Daguerre's work made in 1839 and later. His process, which came to be known as the Daguerreotype process, consisted of exposing a highly polished silvered copper plate, fumed with iodine, in a camera a few minutes, developing the exposed plate with mercury vapor and fixing the image with hypo-sulphite. This complex process involved five distinct operations; cleaning and polishing the plate, coating the plate with sensitive ioduret of silver, adjusting and exposing the plate in the camera obscura, developing the invisible picture after the exposure, and removing the sensitive coating so that no further ch: ge would take place in the picture. Daguerre and Niepce found that they were pursuing experiments of the same nature and went into partnership.
Six months prior to M. Daguerre's publications concerning his process, Mr. Fox Talbot communicated his photographic discoveries to the Royal Society, and afterwards issued an account of his scheme for preparing a sensitive paper for photographic reproduction which he called photogenic drawings. He prepared his paper by washing a sheet of fine writing paper with solutions of salt and silver nitrate. When dried this proved of use in securing prints of leaves, etc., in the camera obscura. Later he used iodide of potassium and other chemicals to perfect his system. Talbot's second process of paper making was patented in 1841, and was known as the calotype. The main advance in this system was the ability of the discoverer to make unlimited prints of his picture. Talbot obtained a third photographic patent on a process for photographing on unglazed porcelain, which a man by the name of Malone improved somewhat and eventually became associated with Mr. Talbot.
The museum collection, besides including many fine and unique examples of these first photographic processes, has much material on modern practical photography, including examples of different printing papers, and plates, stereoscopic pictures, flash-light paraphernalia, X-ray and colored photographs, astrophysical photographs and some early examples of moving picture making.
SCIENTIFIC ITEMS
We record with regret the death of Charles Sedgwick Minot, James Stillman professor of comparative anatomy in the Harvard Medical School, eminent for his contributions to embryology and biology and for public services 'n science; of Dr. Theodore Lipps, professor of psychology and philosophy of the University of Munich, and of Dr. Rudolf Emmerich, professor of hygiene and bacteriology in the University of Munich.
The Hayden gold medal of the Philadelphia Academy of National Sciences has been presented to Dr. Henry Fairfield Osborn, in recognition of his paleontological studies.—The De Morgan medal of the London Mathematical Society has been given to Sir Joseph Larmor in recognition of his researches in mathematical physics—One of the royal gold medals of the Royal Society, has been awarded to Professor Ernest Willliam Brown, of Yale University, in recognition of his investigations in mathematical astronomy
Dr. Allen J. McLaughlin, formerly of the Public Health Service, has assumed the duties of health commissioner of Massachusetts.—Dr. C.-E. A. Winslow has resigned from the College of the City of New York to become director of education in the reorganized State Department of Health.