54 Citiciumiti Society of Natural History. 



pressing the leaves till dry between sheets of bibulous paper. 

 vSuch prepared leaves will give pictures in which the veins 

 and veinlets are dark and the remainder of the leaf light col- 

 ored, just the reverse of the photographs obtained by using 

 the fresh or dried leaves without further preparation. In 

 either case the venation — even in minutice — will be well 

 shown. 



Sometimes young leaves, in other cases fully matured 

 leaves, give the best results. Leaves from the herbarium can 

 be used at will. If the veins or petiole are very much thicker 

 than the remainder of the leaf, they can be shaved down. 

 Other specimens may, in .some cases, need trimming. 



It is neces.sary that the leaf (or other object) to be photo- 

 graphed be brought into very close contact with the sensitized 

 paper, for, otherwise, all parts of the print will not be per- 

 fectly distinct. For this reason, the under side of the leaf — 

 where, as a rule, the veins are more prominent — should be 

 placed next to the clear glass in the printing frame, and the 

 upper surface next to the sensitized paper. A layer of cotton 

 or soft blotting paper can be placed over the back of the 

 sensitized paper, which will insure closer contact with all 

 ])arts of an object that may be somewdiat uneven. 



The time of exposure in bright sunlight will vary from a 

 minute or two (for transparent wings), to fifteen or twenty 

 minutes (for foliage leaves) — depending, of course, on the 

 degree of transparency or tran.slucency of the object. The 

 print can be inspected from time to time and the proper dens- 

 ity of the picture secured. 



After exposure the prints can be fi.xed in a solution of 

 hyposulphite of soda. Or if handsome photographs are 

 desired, they can lie toned in the gold solution commonly 

 used by photographers, and fixed in the usual manner. 



The process is so simple, comparatively inexpensive, some 

 interesting results obtainable, and besides, many of the prints 

 would ])r«)ve useful in a variety of ways to botanists, ento- 

 mologists and others. It is, therefore, believed that the 

 reward will be full\- commensurate with the time and energy 

 expended. 



