Page:Popular Science Monthly Volume 86.djvu/107
THE PROGRESS OF SCIENCE
��of Definition and ^Method in Psychol- ogy- ' '
Vice-president Judsoii G. Wall, be- fore the Section of Social and Economic Science: "Social and Economic Value of Industrial Museums. ' '
Vice-president Theodore Hough, be- fore the Section of Physiology and Ex- perimental Medicine: "The Classifica- tion of Nervous Eeactions. ' '
Vice-president P. P. Claxton, before the Section of Education: "The Amer- ican Rural School. ' '
Vice-president L. II. Bailey, before the Section of Agriculture: "The Place of Research and Publicity in the forthcoming Country Life Develop- ment. ' '
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 sec- tions of the association and the sepa- rate societies, while in themselves af- fording 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, ofl^ers 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 institu- tions have been among the leading edu- cational and scientific centers of the country. It was long our chief city for medical education and research, occupying somewhat the jilace in science that Boston filled in letters. The recent history of chemistry in America, by Dr. Edgar F. Smith, prov- ost of the university and chairman of the local committee for the approach- ing meeting, indicates the city's lead- ership 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 Philadel- phia to rival New York and Washing- ton, it will surely make contributions to science commensurate with its wealth and population
THE PROGBESS IN PHOTOGEAFEY
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 photo- graphs, said to be the most complete in the world, has been collected and classified by Mr. T. W. Smillie, pho- tographer 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 speci- fications for Dr. S. F. B. Moore, in ]839.
The earliest camera, the camera ob- scura, 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 six- teenth century. It is said that the ac- tion 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 con- sequence only imitations of this method are to be seen in the museum collection. Thomas Wedgwood experimented along this same line in 3 802, and prei^ared a paper on the subject.
The first successful inquirer to se- cure permanent pictures through the influence of the sun 's rays, seems to have been Nicephore Niepce, who in 1824 effected the process of heliog- raphy by th use of a varnish made of asphaltum, or bitumen of Judea, ap- plied to a highly polished metal plate or a glass plate, and developed by es- sential oil of lavender and white pe-