330 Cause of Aridity in Western America. — 
and other writers. But I have in no case found the integral pro- i 
gression of a great storm to be in accordance with the specific 
direction of this wind. 
To my own apprehension, it is the constant course of the low- 
er winds towards the equator, on the western shores of America, 
below the latitude of 40°, that best explains the aridity of those 
regions. And itis to a counter course of progression, in the lower 
atmosphere, that the United States, China, and western Europe 
are mainly indebted for their rains and fertility. 'T’o these gene- 
ral and remote causes may also be ascribed the varied electrical 
and hygrometric phenomena of these different regions. 
In closing these imperfect remarks and statements on the 
American tempests, I tender my thanks to all who have aided me 
in the inquiry. To Col. Rein, Governor of Bermuda, and through 
him to Vice Admiral Sir Cuartes Apam, and other officers.of the . 
British Navy, and to the officers and agents of the R. M. steam- 
ships, Iam indebted for valuable logs of various vessels. Sur- 
geon General Lawson, under the favor of the War Department, 
has kindly furnished me with the meteorological reports from our ; 
military stations, and by the aid of Lieut. M. F. Maury and the e 
favor of the Navy Department I have obtained the logs of our . 
national vessels. Prof. J. R. Becx, secretary of the Board of 
Regents, has given me free access to detailed reports from the 
several academies in the state of New. York, and various profes- 
sors and other gentlemen have furnished me with copies of their 
private journals. I am indebted, also, to many merchants, ship- 
masters, and others, for important aid, and can only hope that the 
results attained may prove useful to those who may be engag 
in commercial and other pursuits. 
Practica Depucrions.—It was my purpose to add some further 
practical exposition of the law of rotation and progression 12 : 
storms, which might aid the mariner in avoiding their destrue- ; 
tive violence, and render the rotary winds and gales more sub- 
servient to navigation ; but my proposed limits have already beet 
It is necessary, however, that the character and get- 
eral extent of the rotation, and the usual courses of progression, — 
be-once clearly understood. Perhaps no one case can better i- 
these conditions than the Cuba hurricane, viewed iol 
