i8 



CHAP. II. HIGH MAGNIFICATION CRESCOGRAPH 



was increased to 5 seconds. The middle record N (fig. 7) 

 was taken at the temperature of the room. The temperature 

 was next lowered by a few degrees and the record C shows 

 the result. Finally, the record H was obtained when the 

 temperature was raised a few degrees above that of the 

 room. It will be seen that under the action of cold 

 the space between successive dots became shortened, ex- 

 hibiting a diminution in the rate of growth. Heat, on the 



Fig. 7. Fig. 8. 



Fig. 7. Effect of temperature recorded with stationary plate. 



N, normal rate ; c, retarded rate under cold ; h, enhanced rate 



under heat. (Kysoor.) 



Fig. 8. Record of a single growth-pulse of Zephyranthes. 

 (Magnification 10,000 times.) 



other hand, caused a widening of the interval between 

 successive dots, thus demonstrating enhancement of the 

 rate. 



Calculating from the data supplied by the record : 



The absolute value of normal rate is 0*457 y. per sec. 

 Diminished rate under cold . . 0'ioi(i, ,, ,, 



Enhanced rate under heat . . 0-737 [i ,, 



Experiment 5. Pulsation in growth. — As a further 

 example of the capability of the Crescograph, I give the 



