GERMINATION OF THE SEED 



183 



and a half inches in diameter). Set one cork upright in a 

 fixed position ; push the horizontal rod of a clinostat into a 

 hole previously made in the middle of the other, so it will be 

 kept revolving slowly in a vertical plane. The Beans on the 

 fixed cork will, in three or four days, all have roots 

 turned downward, while on the revolving cork they are at 

 any and all angles, but usually somewhat in the direction they 

 have in the seeds. It is well to keep them covered from light 



FIG. 17. A simple clinostat. x |. 



by black paper, but while under observation by the students 

 the moss may be removed and the glass cleaned and replaced. 

 Using the Horse Beans, which are the best known to me for 

 such purposes, this experiment is, with me, always highly 

 satisfactory. The crystallizing dishes may be omitted, in which 

 case occasional watering is needed, and the moss must be tied 

 to the corks, or aluminum dishes could be used. 



Unfortunately, the only clinostats on the market are expen- 

 sive. Wortmann's is the best ; it costs duty-free about $50, and 



