12 



EXPERIMENTS WITH PLANTS 



discover if any cracks have been formed which might 

 admit water and so vitiate the results. 



It is interesting to calculate the percentage of water 1 

 absorbed and make a comparison after various periods 

 of immersion. 



The following will serve to illustrate the method: 



After soaking fifteen minutes, the weight of the 

 sealed lot was 32.34 grams; subtract from this the 

 weight before soaking (32), which gives the gain 

 (0.34 grams) ; divide this by the original weight be- 

 fore treating with rubber (31 grams) to get the gain 

 in per cent. In this case an area on the unsealed 

 seeds was covered with rubber so as to equal the 

 amount covered on the sealed seeds. 



