hide Matching Documents

The documents where this entity occurs most often are shown below. Click on a document to open it.

Document Max. Freq Min. Freq
Knight's Mechanical Encyclopedia (ed. Knight) 2 0 Browse Search
View all matching documents...

Your search returned 2 results in 1 document section:

Knight's Mechanical Encyclopedia (ed. Knight), P. (search)
. See photolithography; photo-engraving; photo-mechanical printing; photo-relief, etc. In a dictionary devoted to mechanical devices and processes, it would be out of place to expatiate at length on chemical phenomena incidental to the use of apparatus. Purely theoretical considerations, therefore, connected with photography have been ignored in the foregoing article, and the labors of Sir John Herschel, Robert Hunt, and others, in the early days of photography, and of such men as G. Wharton Simpson, Hermann Vagel, and M. Carey Lea. have not been given the prominence they deserve and should have had in an exhaustive treatise. Without, however, going into theory, the attention of the reader seeking general information should be directed to the marked differences which manifest themselves in the nature of the sensitiveness of chemical compounds. In one class, the actinic rays have power to effect at once a complete change. This is true of the mixture of chlorine and hydrogen;