BOTANY. 



609 



were grown under the same conditions as the first, except that the 

 spaces between the walls were filled with water instead of ice, giving' an 

 average temperature of about 16°. The different plants were planted 

 on June 3, and by August 1 they presented markedly different aspects. 

 All those which had received the alternate day and night temperatures 

 were much smaller than those which had been kept at a uniformly low 

 temperature or those grown under normal conditions. In the case of 

 the germander the difference in growth is strikingly shown in the 

 accompanying figure. In the fourth lot of plants, where water was 



Fk;. It. — Eri'ect of alternation of temperature on plants: 1, normal conditions; 2, constant low 

 temperature; 3, daily variation of high and low temperature. 



substituted for ice between the walls, the plants made almost normal 

 growth. The effect of the different conditions on the growth of the 

 plants is shown in the following table: 



Effect of different tempe rat ure conditions on plant growth. 



14270— No. 7- 



