APPENDIX. 259 



water playing in the sink will keep the air moist or may 

 be used to spray the plants arranged around the sides of 

 the sink. The water jet should be connected with the 

 pipes by means of a flexible rubber tube so that it may be 

 moved about at will. 



2. THE LABORATORY. 



A room with northern exposure is to be preferred for 

 the laboratory, as the light from the north gives more uni- 

 form conditions for the use of the microscope. It should 

 be well lighted by large windows and should be supplied 

 with running water. The students' working tables should 

 have flat tops, with a raised rim at the back and sides to 

 guard against dropping reagent bottles and other appa- 

 ratus. A number of cabinets and dark closets are desir- 

 able for storing apparatus and collections of material for 

 study. 



While a fully equipped laboratory is much to be desired, 

 still all the work described in this book may be advan- 

 tageously done in an ordinary schoolroom and on com- 

 mon desks. The entire cost of fitting up a Botanical 

 Laboratory with convenient appliances, including micro- 

 scopes, microtome, and accessory apparatus, is less than 

 the expenditure necessary for a Physical or Chemical Labo- 

 ratory, and the Botanical Laboratory, once equipped, calls 

 for very little expenditure from year to year. 



3. THE MICROSCOPES. 



Microscopes that are powerful enough for all the obser- 

 vations described in this course and that are good enough 

 to place in the hands of beginners may be imported, duty 

 free, for about 118.50. American-made microscopes of 

 equal desirability cost somewhat more. In the selection of 

 microscopes the quality of the objectives is of the greatest 



