318 E. T. Doane on the Atoll of Ebon. 
nation; and for several hundred miles from the earth these 
curves are thus “traced through space in the most distinct wa 
and illuminated with bright electric light "—and further that the 
magnetism of the earth also causes these luminous currents an 
the electrified matter composing the arch to revolve around the 
magnetic pole of the earth, giving them the motion from east to 
west or from west to east, which the a and the compo- 
nents of the arch are observed to hay 
DESCRIPTION OF PLATES. 
Pl. V, Fie. 1. 
, N and S—The North and South magnetic poles of 
the earth. 
n and s—The ee of an imaginary magnet representing the magnetism of 
the 
pa and B —Points on — —— of the earth. 
ab, ed, a c’d’ he —Aurora 
f ond e/f—S Nees of SaEAY'G ieee 
of the zenith to an observer at A 
The arrows show tee position of the bet oe needle = the several er A ad om 
+ and peat the dotted lines represent the magnetic curves passing thr 
= observer a =. yes having its centre at a—the ered ab being 
re epot of of of light, and the streamers surrounding it appearing 
to to apie ‘ioe it ea all 
sees pps a havisiy its centre at ¢, 
Fic. 2 copied from Gassiot’s figure 
Fig. oe presesis an imaginary modification of the same experiment, 
N = S—The shag and South magnetic poles of the earth. 
ands e praeet auroral arches, ne Mi ch stand the stream- 
oa The d dotted hia, represent magnetic curves, and t won one of the arches 
s the direction - besa the streamers, and the components of of the arch revolved 
ts the 28th of Aug., 
Philadelphia, Jan. ri “1861. 
Art. XXVIII.—Remarks upon the Atoll of Ebon, in Micronesia ; 
by E. T. Doane. 
_ WE will begin our res upon the Atoll of Ebon by refer- 
ring in a general way, first, to that section of em wae 
embraces it, known as the ‘Marshall Islands. The name is that 
given by Krusenstern in honor of Capt. Marshall who wits the 
first discoveries there in company with Capt. Gilbert. The dis- 
coveries date back seventy-two years; the first island was seen 
in 1788, the last being discovered only in n 1824 
he whole group lies within the adie 166° and 172° 
east, and 4° 39’ and 12° north latitude. Of the atolls of the 
group, some are large, measuring forty, fifty, and sixty miles in 
circumference, while others are mere ban “reefs, two or three 
miles in circumference. Of the large ‘nlenila we may mention 
Jaluit or Bonham’s Rimski Korsakog, o r Rong-rik and Eong-lab, 
+ 
eee Seas 
