372 BRITISH SEA-WEEDS. 



second shifting, and all the three afterwards, and let the 

 last be a very heavy one. "When the specimens are taken 

 out of the blotting-paper, before they are placed in the 

 herbarium, the scientific name, the locality and the date, 

 should be neatly written at the bottom. 



Though what we have said respecting laying down and 

 pressing is suitable for plants in general, there are excep- 

 tions ; there are some that may be treated in the way we 

 have prescribed, and yet they would not adhere. K they 

 are cartilaginous, or coriaceous, or destitute of gelatine, 

 however firmly pressed, they will not cling to paper ; these 

 require a little gumming, or a little isinglass, which leaves 

 not a 2:lare like £^um. 



Some delicate plants, that lose their fine colour when pre- 

 pared in fresh water, retain it considerably better when they 

 are floated in sea water, or, if this is not at hand, in water 

 in which there is a solution of common salt. ' 



The Great Tangle, and some of the large Fuci, which 

 are not pliant, and which lose their colour, becoming black 

 in the herbarium, are by Algologists that we know dipped 

 in hot water for a little, which both renders them more 

 pliant, and prevcuts them, for a time at least, from becoming 

 black. The natui-al colour might perhaps be in some 



