LABORATORIES AND THEIR EQUIPMENT 83 



ideal place for this work is a small greenhouse open- 

 ing off the laboratory ; and often some angle or gable 

 of the building offers a place for it. In such a house 

 not only could experiments and observations extending 

 over a considerable time be carried on, but a small 

 collection of typical plants to illustrate ecological prin- 

 ciples could be kept to obvious advantage. In place 

 of this, where very large, especially bow, windows are 

 available, a glass partition could be used to make a 

 small greenhouse in the laboratory ; but the heating 

 might offer difficulty. 1 But a simple Wardian case is 

 always a possibility either in laboratory or schoolroom. 

 Its chief qualities are abundant light, hence as much 

 glass and as little frame as possible, sufficient tightness 

 of construction to hold moisture and exclude most of 

 the gases and dust of the room, and some provision 

 for heating in case the temperature of the room falls 

 below about 10 C. at night, or when high temperatures 

 are needed for special experiments. Such a case, 2 built 

 entirely of glass and metal, in use in my own labora- 

 tory, is shown in outline in Fig. 3. The floor is a 

 copper box four inches deep filled with water and heated 

 from below by a Koch safety gas burner, whose flame 

 is shielded from draughts by a sheet-iron hood. The 



1 Valuable hints upon the management of such window gardens, and 

 suggestions as to the best plants for them, are given by J. W. Harshberger 

 in Education, XVIII, 1898. 



2 Made for me by Williams, Brown, and Earle, of Philadelphia. 



