132 ON THE ACTION OF WATER 



the atmosphere, acquires its temperature, and becomes 

 impregnated with air. 



Caroline. Yet rain-water can contain no nourishment, 

 unless it be a little carbonic acid it may imbibe from the 

 atmosphere in passing through it; for rain, consisting of 

 pure vapor exhaled from the surface of the earth, can hold 

 no nutritive particles in solution. 



Mrs. B. Observe that, when rain falls on a plant, it 

 merely refreshes the foliage, by washing off the dust, and 

 cleansing the evaporating pores, which may have been 

 clogged during the drought. Rain cannot feed the plant 

 as it falls from the clouds ; the absorbent pores, you know, 

 are not exposed to its influence : in order to perform this 

 second function it must penetrate into the earth in search 

 of food, and, dissolving whatever it meets with appropri- 

 ate for that purpose, convey it to the roots of the plant. 



Attention must be paid to the proper time and season 

 for watering plants. They do not require it at all in win- 

 der, when growing in the open air ; because, during that 

 season, they cease growing, and, consequently, stand in 

 no need of nourishment ; indeed, they often absorb more 

 water from the wet soil in winter than is good for them. 

 Green-house and hothouse plants should be watered with 

 great moderation in winter : it is time enough to supply 

 them when they ask for it, which you may perceive by 

 their leaves beginning to droop and wither. As spring 

 approaches, the quantity of water must be increased, in 

 order to feed the young buds, which call up additional 

 sap ; but the increase must be made with precaution, the 

 earth being still moist with the winter rains. Plants at 

 this season should be watered in the morning, in order 

 that they may not be overloaded with moisture during 

 the night, which would be dangerous should a frost 

 chance to occur ; besides, by watering in the morning 

 you provide for the evaporation of the day. 



Emily. Yet our gardener generally prefers waterirr 

 in the evening, if he does it only once a day. 



735. What property suited to the nourishment of plants do drop? 

 rain acquire in descending through the air 1 ? 736. In what way t. 

 rain benefit plants -as it falls upon them'? 737. How does rain w j 

 become fitted to nourish them 1 ? 738. Why do not plants in the open 

 air require watering in the winter! 739. What is said of watering 

 green house plants in the winter season! 740. In the spring why 

 should they be watered in ihe morning! 



