20 REPORT OF THE SECRETARY. 



to the various engineering enterprises which are proposed from time to 

 time, as well as to the manufacturing interests of the country. It is 

 also intimately connected with the subject of foreet-culture, which at 

 present is occupying a large share of public attention. It must be the 

 basis of all the improvements which are attempted in regard to irriga- 

 tion, and is of especial value in this respect to the western portion of 

 the United States. 



There are two great systems of rain-bearing winds in North America; 

 that from the west on our Pacific coast, which blows across the .several 

 chains of mountains, constituting the western system, precipitating its 

 moisture principally on the western slopes of the mountains, so that 

 on the eastern sides of these mountains, as well as on the slopes and 

 plains east of the Eocky Mountains, there are arid portions of scanty 

 vegetation, on account of deficient moisture. How far these may be 

 rendered fertile by irrigation depends upon the amount of rain-fall and 

 the conformation of the surface by which the water may be utilized. 

 The other system of rain-winds is from the Gulf of Mexico and the 

 Atlantic. These winds blow principally in the direction of the axis of 

 the Appalachian system of mountains, and consequently precipitate 

 their moisture along the valleys and on both sides of the mountain 

 slopes, covering the whole region with fertility. In connection with 

 this subject we would commend to public attention the plan adopted 

 by the State of Maine in making a hydraulic survey of the whole State, 

 to ascertain the amount of water-power available for manufacturing pur- 

 poses. 



In view of the limited, though in this country comparatively great, quan- 

 tity of coal-power, it is our duty to use, in preference in all cases where 

 it is possible, water-power, which is constantly renewed and must be con- 

 tinued as long as the sun's energy elevates water Irom the surface of 

 the ocean and precipitates it on the higher portions of the land. 

 We have in the falls of Niagara a source of active energy, which we 

 doubt not in the course of years will be utilized to an extent which shall 

 affect the well-being of man in every jiart of the civilized world. The 

 time of the utilization of this power will depend upon the varying price 

 of coal. When this, from the constantly -increasing demand, assumes a 

 certain price, water-power will more generally be resorted to and the 

 large amount of energy which is now dissipated, as in the case of the 

 falls of the Potomac and other rivers, will be carefully husbanded. 



The next work of the same class is tliat of the Winds of the Globe, 

 comprising the results of the discussions of not only observations 

 made under the direction of the Institution in the United States, but of 

 those of every other part of the world of which the records were attain- 

 able. This work has been prepared by the joint agency of the late Prof. 

 Jas. H. Coffin, of Lafayette College, Pennsylvania, and the Smithsonian 

 Institution, the former furnishing the general plan and oversight of the 

 work, the latter contributing the greater part of the material and 



