310 



at any an.tilt' niul at rapid speeds hy using clamps to hold them in posi- 

 tion. 



As stated by Detmer, seedlings of the proper size when fastened on 

 Q and rotated rapidly curve outwards. I have noticed a curving against 

 the direction of motion in seedlings subjected liy a stronger centrifugal 

 machine than this exerting 4,40U gravities. 



At U (Fig. 3) is another similarly arranged dislv in case it is desired 

 to run two at once at different angles. Here, however, the power is trans- 

 mitted by a belt and cone pulleys, by means of which different speeds may 

 be obtained. U may also be inclined at an" angle by loosening or 

 tightening V. At X, X' and Y the shaft is supported in journals. At W 

 is a water wheel 50 cm. in diameter, and by using a very strong stream of 

 water Z, a very high speed and ample power for the experiments here 

 mentioned may be developed. Naturally the speed and power can be 

 easily controlled by the force of the stream of water. By means of the 

 cone-pulleys the machine may be driven by motor or other power. 



IV. Apparatus for Growing Plants in Different Colored Lights. 



This consists of a wooden box made perfectly tight to prevent the 

 light from entering except at H, Fig. G. It is 40 cm. long, 25 cm. wide and 

 25 cm. deep. Of course it is often advisable to use larger sizes of boxes, 

 l)ut the one here mentioned will serve as an illustration. The inside 

 of the Ijox is painted black and is provided with a base for holding 



Fiff. 5. 



flower pots in any position. Each side of the box is provided with a door 

 A. Fig. 5, which by means of the clamps B and B'^ may be removed so 

 that the plant inside may be adjusted in the desired position, as regards 

 the light entering at C or D, and measurements taken. The ends of the 

 box are in the form of caps E (Fig. 5) which lap over the end at F so 

 tightly that no light can enter. 



Fig. (! shows an end view of one of the caps E. In tliis figure 

 there will he noticed a circular opening H. 15 cm. in diameter in the 



