8 4 



THE TEACHING BOTANIST 



height of the flame is controlled by a Reichert thermo- 

 regulator inside the case, which can be set at any de- 

 sired point, and which 

 keeps the temperature 

 within 3 C. of that 

 point, no matter how 

 low it falls in the room 

 outside. This case is, 

 however, more elab- 

 orate than necessary, 

 and, after my expe- 

 rience with it, I believe 

 one would work well 

 if built in the follow- 

 ing manner. Have 

 made a covered, gal- 

 vanized-iron box the 

 length of the window, 

 two feet wide and 

 three inches deep, with 

 a hole in one corner 

 for filling, and a tight 

 sheet - iron hood be- 

 neath to shield the 

 flame and keep gases 



Fi<:. 3. A successful Wardian case. Scale, 



from 



rising 



through 



^ inch = i foot. 



the joints of the case; have sashes made with as little 

 wood as possible to surround and cover it, as shown 



