402 ANNUAL OF SCIENTIFIC DISCOVERY. 



five days in each of the one hundred courses five hundred days about, or 

 near, the time the moon was ascending through the plane of the earth's orbit 

 amounted to 47 'GO inches, while the same number of days in the opposite 

 part of her course, i. c., when she was descending through the plane, only 

 gave 26'42 inches. The wettest point just preceded the ascent of the moon, 

 and the driest the descent of that luminary through the plane of the earth's 

 orbit. Whatever may be the more immediate cause of the above mentioned 

 difference whether the ascent of the moon, through the plane, towards the 

 Northern Pole produces aerial currents from south to north, or whether it 

 diminishes the atmospheric pressure, and thus promotes evaporation and an 

 excess of rain it is reasonable to infer that when she is thus, in some way, 

 producing such excess in this hemisphere, comparatively dry weather obtains 

 in the southern hemisphere, and vice versa, and that intermediate latitudes 

 experience intermediate effects." 



GALES OF THE ATLANTIC. 



During the past year Lieut. M. F. Maury, the director of the National Ob- 

 servatory, has published a series of charts of the North and South Atlantic, 

 exhibiting by means of colors the prevalence of gales over the more stormy 

 parts of the oceans, for each month in the year. One color shows the region 

 in which there is a gale every six days, another color every six to ten days, 

 another every ten to fourteen days, and there is a separate chart for each 

 month and each ocean. The author observes that this is the first attempt to 

 delineate the rain regions over these oceans, and that although the result has 

 cost much labor, it is necessarily imperfect in consequence of the few obser- 

 vations as data on which he has had to rely. It is an initial step in an im- 

 portant work. 



ON THE ZODIACAL LIGHT. 



At the Montreal meeting of the A. A. A. S. Capt. Wilkes, U. S. N., pre- 

 sented a paper on the Zodiacal Light, of which the following is an abstract : 



In the outset he stated that the suggestions he had to present were the re- 

 sult of numerous observations taken during the prosecution of the United 

 States Exploring Expedition to the South Seas, several years ago, and that 

 the conclusions to which he had arrived then were abundantly confirmed by 

 more recent observation. 



All the observations of the zodiacal light showed that it had not changed 

 its appearance since two centuries ago, when first noticed by Cassini ; and by 

 observing it particularly, with reference to the great circles of the globe 

 ecliptic and equinoctial it becomes manifest that all changes of its appear- 

 ance depends solely on the position of the spectator on the surface of the 

 globe. The theories which have been entertained of this light are various. 

 Some derive it from the atmosphere of the sun holding that it is illumin- 

 ated matter thrown off from his equator, revolving with immense velocity, 

 which takes a particular shape. Others have held that it is a nebulous ring, 



