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APPENDIX 



5. 



To investigate the internal structure of a lichen. 



6. To discover how certain kinds of flowers are pollinated. 



7. To find as many kinds of insect galls as possible. 



Instrumental Methods.-^ It is not essential that a beginning class 

 in ecology be provided with expensive equipment. The use of 

 instruments for the measurement of physical factors is so important, 

 however, that, if they can be provided, students should have an 

 opportunity to do at least some work with them, and in almost 



Fig. 116.— a cog psychrometer. 



every case at least some instruments can be provided. In order to 

 obtain accurate and valuable data on most of the physical factors 

 it is necessary to take long series of measurements. This is usually 

 impossible for a beginning class. Two methods have been used with 

 classes at two universities for teaching the use of instruments and the 

 significance of instrumental measurements. By one of these methods 

 five diverse habitats were selected and the class was divided into five 

 groups, one for each habitat. Each group was provided with a 

 photometer for taking light readings, an anemometer for measuring 



