SEA-WEEDS. 95 



of the letter S ; now they are perfectly straight ; 

 and the next moment finds them twisting them- 

 selves up in various contortions, either with slow 

 or rapid motions. When these oscillatory plants 

 are fully grown, their movements cease ; but the 

 young fibres exhibit them, not only while in water, 

 but when taken out and laid on a plate. These 

 plants are of most rapid growth, acquiring ten or 

 twelve times their length in so many hours. They 

 grow and increase like vegetables, but when burnt 

 yield the odour of decaying animal substances. 

 Still more wondrous is that tribe of microscopic 

 Algae called the Diatomacece. Many of these are 

 marine, and are to be found in all seas ; even the 

 melted icebergs yielding masses of them. Thou- 

 sands of these minute plants are contained in a 

 drop of water, yet every little plant has a beautiful 

 structure of flint, and exhibits a most singular 

 conformation. Some of the delicate silk-like or 

 velvety tufts of the Algae of the seas, when ex- 

 amined, seem like strings of beads ; some like tubes 

 of glass filled with bright colouring matter ; others 

 composed of networks finer than the finest cob- 

 webs ; some like little bunches of slender hairs ; 

 others branched, like minute trees of emerald 

 green or sparkling brown, or rivalling the rose and 

 violet in richest hues. We might linger over de- 

 scriptions of the minute wonders of this tribe, and 

 tell how some small plants have filaments consist- 

 ing of two tubes, one of which is exterior and so 

 transparent that it might be compared to a tube 

 of glass. Within this lies a jointed tube, filled 

 with colouring matter, often almost imperceptible, 

 but occasionally of most brilliant green or purple, 

 or faint yellow tint ; and pointing from these won- 



