TRANSPIRATION. 221 



containing O'l per cent, solution of potassium chloride in distilled 

 water. After several days (about 6) measure the volume of solution 

 left in the jar, then evaporate it to dryness and weigh the residue 

 of salt ; or analyse it volumetrically by titration with decinormal 

 silver nitrate, using potassium chromate as indicator. Calculate 

 the proportion of salt left in the solution, and note that it is about 

 twice as great as in the original solution. 



(2) Pull up and rinse in water three similar Bean seedlings germi- 

 nated in moist sawdust. Get ready three small jars, each holding 

 about 120 c.c. ; into each pour 50 c.c. of water, gum a strip of paper 

 at the water level, throw the water out, then fit each jar with a bored 

 cork, and into the hole pass a seedling. Into A pour 100 c.c. of 

 0"25 per cent, solution of potassium nitrate in distilled water ; into 

 , 100 c.c. of O'Oo per cent, solution ; into C, 100 c.c. of 0'025 per 

 cent, solution. Place the three jars in the light, and in each case when 

 the level of the solution falls to the 50 c.c. mark, take out the 

 plant, rinse its root in a little distilled water, and add this water 

 to the solution ; then pour the solution into a weighed evaporating 

 dish or a flask, boil to dryness, and weigh again. From the data 

 thus gained, we find that the plant absorbs from the 0'25 per cent, 

 solution relatively much water and little salt, the solution left 

 being more concentrated than that originally offered to the root. On 

 the other hand, with weaker solutions the plant absorbs relatively 

 more salt than water, so that the remaining portion of the solution 

 is more dilute than that originally present. 



