218 PREPARATION OF LANTERN SLIDES [Cn. VIII 



specimens are now mounted. This gave a very transparent and 

 vivid picture. 



337. Labeling lantern slides. Besides the mark or spot as 

 guide to inserting the slides in the carrier, every lantern slide should 

 have a label stating what it is, and if copied from some book or 

 periodical it should give the name of the publication from which 

 derived and the number of the figure. 



Slides are also numbered for convenience in arrangement at the 

 time of an exhibition. Some workers simply number the slides 

 and have no label. This is, of course, feasible for a small collection 

 to be used by one individual, but the slides are practically useless 

 for any one else unless they are labeled. 



Sometimes slides are numbered, and a catalogue kept with cor- 

 responding numbers and a description of the slide. For one 

 unfamiliar with the collection the numbers and the cards are not 

 easy to put together. Then one is liable to have more than one 

 series, and the series are liable to get mixed. With a label on each 

 slide, the collection can be made use of by any one. 



338. Storing lantern slides. The problem of storing a large 

 collection of lantern slides is a serious one. A still more serious 

 problem is to find the slides needed for a given lecture or demon- 

 stration. 



A common method of storing is to have a cabinet like that used 

 for the card catalogue of libraries, and to put the slides in the draw- 

 ers as the catalogue cards are filed. 



One can use name cards to designate groups of slides as they are 

 used to group catalogue cards. 



In order to store and make them most easily available for use, Pro- 

 fessor George S. Molcr of the department of Physics in Cornell 

 University has devised a cabinet which holds the slides in a single 

 vertical layer, so that when any holder is pulled out the slides are 

 all exhibited, and one can see exactly what the slides are and select 

 those desired. 



This seems to the writers of this book, by all odds, the most prac- 

 tical cabinet yet devised for safely storing slides and making them 

 available with the least trouble and the least waste of time (fig. 120). 



