2 MOSSES WITH A HAND-LENS 



often prove an insoluble puzzle to the advanced student and 

 would be nothing but a source of discouragement to the begin- 

 ner. Many mosses of the more difficult genera like Hypnum and 

 Bryum are not included in this book because they can not be 

 recognized with any degree of certainty without the aid of the 

 compound microscope. As some of these difficult species are 

 common they will prove a source of annoyance to the beginner, 

 and it is hoped will lead him to obtain, sooner or later, the 

 necessary books and apparatus for a more extended study. 



Almost any form of simple microscope will serve for the 

 study of most of the mosses with this book, but to obtain the 

 best results it should be of a construction suitable for carrying 

 in the pocket into the field. 



The hand-lens recommended for this book is of so short a 

 focus that it can not readily be used for a dissecting lens, so that 

 some form of dissecting microscope will prove very useful. If 

 one can not afford a regular dissecting microscope costing from 

 three to five dollars, a tripod costing less than one dollar will 

 give good results. Place the object to be dissected on a piece 

 of plain glass over white paper and stand the tripod on 

 the glass. 



For ordinary work a lens of from 15 to 20 diameters is 

 needed, for the finer details a lens of 30 or more diameters is 

 necessary. In studying very minute parts it will often be neces- 

 sary to mount in water in the same manner as for the compound 

 microscope. For the preparation of these slides the student 

 should have half-a-dozen blank slides of glass, such as can be 

 purchased of any dealer in optical goods, a small pair of fine flat- 

 pointed forceps and two fine-pointed dissecting needles. A small 

 scalpel is useful, but a good pocket knife will answer all pur- 

 poses. Circles or squares of thin glass are useful, but two slides 

 can be used with the object mounted in water between them. 

 Mica can be used for covers or for slides and covers both. 



In preparing these slides all specimens not fresh and moist 

 should first be soaked out in hot water, the parts to be studied 

 should then be carefully removed with the forceps and placed in a 

 drop of water on one of the glass slides and covered with a cover 

 circle or another slide. If one has a dissecting microscope with 

 stand and mirror the slides can be studied in the usual manner, 

 but almost as good results can be obtained by holding the slide 

 up to a strong light and examining it thus as a transparent object. 



