13th, 6 A.M. Clear, east and north; bank of cirrus in N.-W., _i.e._, from N.-N.-E. to W. by S.; irregular branches of cirrus clouds, reaching almost to south-eastern horizon; wind changed (S.-E. fresh); 8 A.M., the sky a perfect picture; heavy regular shafts of dense cirrus radiating all around, and diverging from a thick nucleus in north-west, the spaces between being of clear blue sky. The shafts are rotating from north to south, the nucleus advancing eastward. Appearance of the central vortex descending at 8 A.M., July 13th, 1853: In Fig. 18, the circle represents the whole sky from the zenith to the horizon, yet it can convey but a very faint idea of the regularity and vividness of this display. The reflected image of the sky was received from a vessel of turbid water, which will be found better than a mirror, when the wind will permit. [Illustration: Fig. 18] At noon (same day) getting thicker (S.-E. very fresh); 6 P.M., moon on meridian, a prismatic gloom in south, and very thick stratus of all shades; 9 P.M., very gloomy; wind stronger (S.-E.): 10 P.M., very black in south, and overcast generally. 14th. Last night about 12 P.M. commenced raining; 3 A.M., rained steadily; 7 A.M., same weather; 8.20 A.M., a line of low storm-cloud, or seud, showing very sharp and white on the dark back ground all along the southern sky. This line continues until noon about 10° at the highest, showing the northern boundary of the storm to the southward; 8 P.M., same bank visible, although in rapid motion eastward; same time clear overhead, with cirrus fringe pointing north from the bank; much lightning in south (W. fresh); so ends. 15th. Last night a black squall from N.-W. passed south without rain; at 3 A.M. clear above, but very black in south (calm below all the time); 9 A.M., the bank in south again throwing off rays of cirri in a well-defined arch, whose vortex is south: these pass east, but continue to form and preserve their linear direction to the north; no lightning in south to-night. 16th. Clear all day, without a stain, and calm. 17th. Fine and clear (N.-E. light); 6 P.M., calm. 18th. Fair and cloudy (N.-E. light); 6 P.M., calm. 19th. Fine and clear (N. fresh); I. V. visible in S.-W. 20th. 8 A.M., bank in N.-W. with beautiful cirrus radiations; 10 A.M., getting thick with dense plates of cream-colored cirrus visible through the breaks; gloomy looking all day (N.-E. light).[21] Appearance of the Inner Vortex at 8 A.M., July 20th, 1853, including the whole sky. (See Fig. 19.) [Illustration: Fig. 19]