This is a 1911 publication and is arranged in alphabetical order as in a dictionary. No subject is explored in depth but it is very useful for researching terms related to photography. Chemical reagents, photography genres, optics, cameras, all kinds of accessories, processes, etc. There are 636 pages especially useful for those studying the history of photography as it presents terms and concepts that have fallen out of use for over 100 years.
It can be downloaded for free at: archive.org