THE SHORES OF BRITAIN. 33 



investigations of botanists ; but it is now ascertained 

 to consist of little pear-shaped capsnles, imbedded in 

 the surface, and much crowded, which the gradual 

 melting away of the skin allows to escape. One 

 of the most interesting circumstances connected with 

 the history of the sea-plant is, the beautiful and 

 varied apparatus with which many of them are pro- 

 vided for securing buoyancy. It seems to be essential 

 to their health that they should at least approach 

 the surface, but as their substance is specifically 

 heavier than water, many of them are greatly length- 

 ened, and furnished with hollow vessels inflated with 

 air, by which their weight is diminished. These 

 differ much in form and position in the various 

 tribes ; in the Sea--wTack {F. vesicidosus) , we saw 

 them tike the form of bladders, arranged in pairs 

 on each side of the midrib ; in the Ivnotted-wrack 

 {F. nod.osus) the stem swells at inters^als into hollow 

 bulb-like dilatations ; while in the long Sea-lace 

 before us, the same end is answered by dividing the 

 hollow tube into chambers, interrupted at short dis- 

 tances by portions of the solid substance of the frond ; 

 the cavities being filled in some unknown manner with 

 air, probably hydrogen generated by the plant itself 

 Many of the AJgce are rather extensively used as 

 food ; and though to one unused to such diet they 

 would in general seem to offer little temptation to 

 the appetite, the poorer natives, not only of our own 

 but of other shores, eat them with much relish. Let 

 us not despise their taste, though differing from our 

 own, but rather adore the beneficence of God, who 



has supplied in much abundance an additional source 



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