THE PRESERVATION OF MARINE OBJECTS 87 



be partially dried in the calico press, and then laid on the paper on 

 which they are to be finally mounted, and re-pressed with a piece 

 of dry calico on the top of each specimen. 



Many of the smaller weeds may be treated in the manner just 

 described, but the more delicate species require to be dealt with 

 as follows : Place each in a large, shallow vessel of water, and 

 move it about, if necessary, to cause its delicate fronds to assume 

 that graceful form so characteristic of the algae of our rock pools. 

 Then immerse the sheet of paper on which the weed is to be 

 finally mounted, and slowly raise the specimen out of the water, 

 on the paper, without disturbing the arrangement of the fronds. 

 If it is found necessary to rearrange any of the fronds, it may be 

 done by means of a wet camel-hair brush. Now lay the specimen 

 on calico or absorbent paper, placed on a sloping board, to dram ; 

 and, after the greater part of the moisture has disappeared by 

 draining and evaporation, transfer the specimen to the press with 

 a piece of dry calico immediately over it. All are dealt with in 

 turn in the manner described, and allowed to remain in the press 

 until perfectly dry, when it will be found that the majority of them 

 have become firmly attached to the mount, and require nothing 

 but the label to fit them for the herbarium. 



Sea-weed collectors often make the great mistake of pressing 

 tufts that are far too dense to admit of the structural characters 

 being satisfactorily examined. To avoid this fault, it will often be 

 necessary to divide the clusters collected so that the forms of their 

 fronds may be more readily observed. 



The calcareous corallines may be pressed in the same way as 

 the other algae, but very pretty tufts of these, having much the 

 appearance of the living plant, may be obtained by simply 

 suspending them until thoroughly dry ; though, of course, speci- 

 mens so prepared must not be submitted to pressure after they are 

 dry, being then so brittle that they are easily broken to pieces. 



The hard framework of these interesting corallines is composed 

 principally of carbonate of lime, a mineral substance that dissolves 

 freely in hydrochloric acid (spirits of salt). Thus, if we place a 

 tuft of coralline in this acid, which should be considerably diluted 

 with water, the calcareous skeleton immediately begins to dissolve, 

 with the evolution of minute bubbles of carbonic acid gas; and 

 after a short time, the end of which is denoted by the absence of 

 any further bubbling, nothing remains but the vegetable matter, 

 now rendered soft and pliant. A decalcified specimen of coralline 



