1834 



Journal of Applied Microscopy 



At the west end of the main laboratory one enters a dark room of liberal 

 dimensions which may be used for photographic purposes, as well as physiological. 

 In this room also there is a moist chamber, fashioned like the one described 

 above. 



From the dark room a door leads to the teri*arium or " Wurzetunnel," a por- 

 tion of which appears in our reproduction, Fig. 5. The purpose of this feature 

 is to make possible the careful study of economic plants in relation to the soil, 

 especially regarding the problems of nutrition. The plan of the terrarium makes 

 it possible to grow the plants under investigation out of doors, and yet have the 

 soil and watering completely under control. This is accomplished in the foUow- 



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Fig. 8.— Floor Plan. 



ing manner. Along one side of the terrarium are six tanks built of brick and 

 cement. The sides toward the room are of plate glass, and are, with one excep- 

 tion, placed in sloping position ; this the better to study the behavior of the root 

 systems. To guard against phototropic reactions, the roof of the terrarium is 

 made of yellow glass, which, therefore, admits only inert light in this regard. 

 Ventilation is had by means of a ventilator, which admits no light, in the door. 

 Taps at the tank bottoms, which have a proper slope, allow the water to be 

 drawn off for analysis if it is so desired. 



Externally the compartments are made easy of access by sliding backs, which 

 may be removed when it is desired to work at the cultures. The arrangement 

 as it appears is shown in Fig. G. 



