Page:Popular Science Monthly Volume 38.djvu/511

Rh conditions. The pots of clover and lucern were left for a second year's growth, and their roots could not, therefore, be examined. A photograph of the four pots of peas was made October 22d (a copy of which is given in Fig. 1), and the plants were taken up for examination October 23d and 24th.



The relative growth and development of the plants in the different pots are clearly shown in the photograph. "Unlike the result obtained in pot 1 in 1888, with the impure and non-sterilized sand, the plants in the purer and sterilized quartz sand (pot 1,