58 LECTURE IV. 



From these figures it appears that nitrate of potassium is absorbed 

 according to de Saussure's law at a concentration of 0^25 per cent., but 

 that at a concentration of 0*1 per cent, and below it is absorbed in larger 

 proportion than the water in which it is dissolved. This is even more 

 strikingly shewn by nitrate of ammonia. 



Amount of salt 



water iiusurucu absorbed 



during expt. during expt. 



Nitrate of ammonia, 0*2456 per cent. 70 c.c. 0*236 grm. 

 0*0982 85 0*094 



0*0491 48 0*045 n 

 0-0245 55 56 0*022 



In this case the strength per cent, of the solutions actually absorbed is 



'337 I 5 giving a difference of +0*0915 



0*1 106 +0*0124 



0-0937 +0-0446 



0-0392 +0-0147 



The absorption of this salt does not take place in accordance with 

 de Saussure's law even at a concentration of 0*2456 per cent. 



With the Maize, Wolf obtained the following results which closely 

 resemble those obtained with Phaseolus. 



Strength of Amount of Time required 



solution salt absorbed to absorb 50 c. c. 



Nitrate of potassium, 0*100 p. c. o 1 138 grm. per 100 of water 12 days 

 ,5 o'75 ,5 o >10 6 10 



,5 0*050 0*096 8 



55 ' 02 5 55 0*047 55 74 55 



Nitrate of ammonia, 0*0735,, o'ii8 12^ 



0*0491 0*080 12 



0*0245 55 0-042 10 



The strength of the solution actually absorbed in each case is indicated 

 by the figures in the second column. 



In the above experiments with Phaseolus the time of absorption was 

 uniform ; it may therefore be well to add, for the purpose of direct com- 

 parison with the Maize, some experiments with Phaseolus in which the 

 quantity of solution absorbed was as nearly as possible uniform. 



Strength of Amount of Amount of Strength of TKffi.rf.nro 



solution water absorbed salt absorbed solution absorbed 



Nitrate of potassium, 



o- 1 oo per cent. 49 c.c. 0-053 grm. o'i 08 per cent. +0*008 



0-075 50. 0-048 0-096 +0-021 



0-050 50 0-041 0*082 +0*032 



0*025 51 0*022 0-043 55 + 0*01$ 



