64 REPORT OF NATIONAL MUSEUM, 1914, 
The first permanent heliographs by the so-called asphalt process, 
which seemed to present exceptional opportunities for illustrative 
purposes, are depicted by a single print made by Joseph Nicéphore 
Niépee in 1824. The subject of the daguerreotype is well and fully 
represented by various pieces of apparatus, including a camera used 
by S. F. B. Morse in 1839, and a large series of pictures. This proc- 
ess, invented by L. J. M. Daguerre and published in 1839, consists 
briefly in fuming with iodine one surface of a copper plate which 
has been silvered and highly polished, then exposing it in the camera, 
developing with vapor of mercury, and fixing in a solution of hypo- 
sulphite of soda. The exposure at first required about 15 minutes, 
but experiments made by others soon afterward reduced the time to 
less than a minute, and made the pictures more permanent and much 
more beautiful. The calotype or talbotype, the invention of Wil- 
liam Henry Fox Talbot, of England, published in 1840, marked one 
of the most important advances in photography, as it provided for 
a negative made of paper from which any number of prints could 
be taken. The Museum is fortunate in having examples of the ap- 
paratus, negatives, and prints, the latter made by Mr. Talbot him- 
self, and including views of his home, Lacock Abbey. The stereo- 
scope with stereoscopic views follows next, as its invention in 1838 
Was contemporaneous with that of photography, though originally 
designed for viewing drawings. In the last case of this series are 
examples of albumen positives on glass and prints from albumen 
negatives, invented by Niépce de Saint Victor in 1848; of ambro- 
types, introduced by Cutting and Rehn in 1850; and of vitrified 
enamel photographs, invented by Lafon de Camarsac in 1854; be- 
sides a series of tintypes by Peter Neff, the discoverer of that 
process. 
At this point is reached the beginning of the wall case, in which 
and in the few additional floor cases, the collection is continued in 
about the following order: In the first section is a series of plain 
silver prints, some of which were made at an early date from collo- 
dion glass negatives and called crystallotypes. They were used to 
illustrate the Photographic and Fine Art Journal in 1857 and other 
publications of that time. Some later prints have also been intro- 
duced. The next three sections are devoted to the wet-collodion 
negative and albumen silver print, representing processes that were 
employed for many years. The use of collodion as a vehicle to hold 
the silver haloids on plates originated with Frederick Scott Archer 
in 1850, while the silver printing process was introduced about 1852. 
In this connection is likewise displayed a series of composite photo- 
graphs. 
Carbon printing is illustrated in the adjoining section by prints 
of the various processes. This form of printing is the result of 
