THE PROGRESS OF SCIENCE 



103 



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- 



