64 NATURAL HISTORY OF 



that one of the most important qualifications of the " look- 

 out " in vessels in the dangerous regions where it prevails is to 

 be able to distinguish floating from rooted specimens of the 

 plant. 



On the l7th, the water having assumed a muddy appear- 

 ance, I examined a small portion with the microscope, but 

 could not detect anything with the exception of numerous 

 grains of sand. The forenoon of the following day was bright 

 and sunny, and we had a capital breeze, which allowed us to 

 make from eight to nine knots an hour. During the after- 

 noon, however, the barometer fell very rapidly, and the sky 

 presenting a most threatening aspect, sail was shortened at 

 about 5 P.M., and preparations made for a gale, which, how- 

 ever, did not take place, the clouds discharging themselves in 

 heavy rain, which lasted for some time, and was succeeded 

 by a red, stormy sunset. 



The 19th was also a bright bracing day, making us expe- 

 rience the physical pleasure of existence, which is not so easy 

 of attainment in the tropics. Towards evening the weather 

 again assumed an unpropitious aspect, the heavens becoming 

 covered with most remarkable masses of heavy cloud, with 

 here and there intervals of pale mild green sky. At length, 

 just as the sun was going down, a squall came on, and the 

 scene that ensued while the vessel tore through |the per- 

 turbed water, was of the most weird and striking character, 

 for along the horizon stretched a broad brilliant orange belt 

 of sky, banded above by heavy black clouds, and across it 

 and the setting sun a thin veil of falling rain extended. At 

 the close of the squall, which did not last long, the orange 

 colour was succeeded by a splendid green hue. 



On the 20th, a fine day but the wind foul, so that we 

 were much off our course, a number of small grayish-white 



