WATER AND AIR. 125 



winter no more generally than what results from the capillary attrac- 

 tion of the particles of the soil. The younger the leaves of plants 

 the more active their perspiration. A constant supply of water ren- 

 ders the parts of plants succulent, as with the leaves sent to the 

 table, and also fruit. To effect this artificially, or its appearance, 

 market-gardeners and hucksters are in the habit of pouring copious 

 and frequent showers of water upon them, but generally at the sacri- 

 fice of their quality. The quantity of water in the soil of succulent 

 fruits should be diminished when they are ripening. The solar light 

 should correspond with the quantity of moisture, otherwise the tissue 

 becomes disorganized. When in great excess water gives to plants a 

 yellow appearance, owing, it is thought, to the destruction by water 

 of the blue matter, by the mixture of which with yellow parts the 

 green verdure of plants is formed. Undue moisture about the roots 

 is relieved by draining and no good fruit can grow in soils imperfectly 

 drained. It has been thought, too, that the watering of plants artificially 

 in the open air is of very questionable advantage, as the air is not fur- 

 nished with corresponding moisture. The roots are thus but momentarily 

 excited while the sudden evaporation from the soil produces cold, and the 

 surface becomes incrusted, which are not the results of watering by 

 natural showers. In late spring planting it is far better to water in 

 the hole. In the case of annual plants only is watering recommended, 

 and then chiefly by inundations through sluices etc. Copious water- 

 ing thus prevents mildew. 



Atmospheric moisture varies greatly in different regions, while the 

 constituents of the air rarely vary ; yet these are intimately connected. 

 The effect of excessive perspiration in plants is to dry up their juices, 

 while an obstruction of the perspiratory organs, the leaves chiefly, 

 prevents the assimilation of fluids and the formation of new matter. 

 This is closely analogous with the same process in the animal economy. 

 An atmosphere which maintains perspiratory action in the most uni- 

 form and healthy state, is that most desirable. By Daniell's hygrom- 

 eter all the points of moisture may be ascertained, which will be 

 found of great practical importance. The changes of moisture ex- 

 tend in this latitude from 1000, or saturation, to 389 and often lower. 

 The mean depth of rain and snow in this state (N.Y.) for 14 years has 

 been 84.40 inches. The highest average from 54 stations for one single 

 year (1827) was 44.40, and of the lowest (1839) 22.10 inches. In 

 London it is 24.01; St. Petersburg 16; Algiers 27; E. Indies 31 to 

 64; Madeira 31; Bahamas 54.99; Calcutta 59.83 to 81 ; Ceylon 

 84.3 ; Macao 48.8 to 107.3 ; Equator 96; Coast of Malabar 123.50; 

 Grenada 126 ; St. Domingo 150 ; Bengal 20 to 22, in a single month ; 

 Bombay 32, in 12 days, and in Savoy 205 inches in 6 months, or 8.5 

 in a day, oftentimes ! 



The effect of wind is to increase in the same ratio the dryness of 



