-1859] WRITINGS OF JOSEPH HENRY. 287 



from the Gulf of Mexico and the Caribbean Sea over the 

 whole of the Eastern States of the Union and the eastern part 

 of the Valley of the Mississippi, and is therefore the princi- 

 pal fertilizing wind of the interior of the continent. Were 

 the earth at rest this wind would flow directly northward, 

 and would diffuse its vapor over the whole interior of the 

 country to the base of the Rocky Mountains; but on account 

 of the rotation of the earth it is thrown eastward, and bears 

 its moisture in a northeasterly direction, leaving a large 

 space, under the lee of the Rocky Mountains, (so to speak,) 

 greatly deficient in this element of vegetable production. 



These winds are shown on the accompanying map of the 

 United States, which is copied in its principal features from a 

 large map compiled by the Smithsonian Institution. In so 

 small a sketch it is impossible to be accurate in the minute 

 divisions ; though it will serve to exhibit at a glance the rela- 

 tive proportions of the principal meteorological regions of 

 the country. The northwest winds (those of the upper strata) 

 are denoted by the heavier arrows with a circle on the end, and 

 the lower ones — the surface or fertilizing winds — by the finer 

 arrows. The dark portion of the map indicates the naturally 

 woody regions of the country, well supplied as a whole with 

 moisture from the fertilizing winds: the lighter shaded parts 

 indicate rich arable prairie, along the streams of which, 

 (where there is a local supply of vapor,) wood is found ; but 

 these districts as a whole have much less moisture than the 

 naturally woody portions. The unshaded or white part of 

 the map, within the boundary of the United States, indicates 

 the regions so deficient in moisture that no dependence can 

 be placed upon them for the purpose of agriculture. In 

 some parts of them, where moisture is found, crops may be 

 produced, but as a whole they are of little value in the way 

 of affording the necessaries of human existence, and hence 

 are incapable of sustaining other than a very sparse popu- 

 lation. Portions of this unshaded part, on account of the 

 nature of the soil, are barren and almost destitute of vege- 

 tation ; while other parts, when occasionally watered by a 

 fitful shower, yield patches of grass to which the buffalo by 



