20 



night ; resting satisfied in their being immutable, 

 and that the devices of man can never vary their 

 order or their influence. 



Meteoroloo'y, for somewhat similar reasons, has 

 also been commonly excluded from the pale of Nat- 

 ural History. But this science, in its whole extent, 

 has a most important bearing upon vegetable culture. 

 Water and air are the very blood and breath of life 

 to plants. The different states of the atmosphere as 

 indicated by the barometer, thermometer, hygrome- 

 ter and electrometer ; — the action of light and heat, 

 whether solar or artificial, whether accumulated or 

 diminished, whether applied after long or short in- 

 tervals ; — the influence of the diflerent winds, and 

 the effects of exposure to or protection from them ; — 

 the phenomena of clouds, fog, dew, frost, rain, snow, 

 and hail, are among the subjects which most nearly 

 affect the operations of the gardener, and whose 

 nature and powers it behooves him thoroughly to 

 understand. 



But some of the first considerations demanding 

 his attention relate to the materials of which the sur- 

 face of the earth, on which he operates, is composed. 

 The necessity of an acquaintance with Mineralogy is 

 here manifest ; — preparatory for which a knowledge 

 of Chemistry is requisite, as well as for the analysis 

 and composition of soils, and also of vegetable pro- 

 ducts. Next, it will soon be found that the proper- 

 ties of soils vary not only Avith the elevation and as- 

 pect of the surface, but are also greatly modified by 

 the nature of the rocky or other strata on which they 



