HARD WICKE 'S S CIENCE- G OSSIP. 



109 



The mould having been made as firm and steady 

 as possible, the operator now mixes another batch of 

 plaster-of- Paris. At first it is best to mix too much 

 rather than too little, for if there is too much it need 

 not be all used, but if there is too little the cast will 

 set whilst more is being mixed, and the entire labour 

 may thus be lost. The plaster should be of about 

 the same consistency as when it was used for making 

 the mould. It is poured into the latter gently and 

 evenly, until it is completely filled, and the process 

 is continued over the square-bar space, until it covers 

 the latter, say an inch in thickness. By means of a 

 trowel, or any other tool, the plaster is smoothed 

 down to an equal level. With a knife, the over- 

 flowing plaster should then be pared off before it 

 sets hard, so as to be flush with the square sides of 



When the mould has at length been stripped off, the 

 operator has the perfect cast of the fish as first laid 

 down. Every scale and fin is present, whilst the 

 space between the movable wooden bars (which we 

 recommended should be covered over on the mould) 

 is now a square background, from which the cast of 

 the fish stands forth in high relief. A littile trimming 

 and truncating of the edges makes it perfect. Any 

 cavities left either in the cast or the base to which it 

 is attached, may now be filled up and smoothed down. 

 Sometimes the tips of the fins break off when peeling 

 away the mould. In that case the student must re- 

 pair them as best he can, by adding a little plaster, and 

 carving it down when dry. The feelers or barbules 

 of such fish as Cod, Whiting, &c, may best be imitated 

 by fixing a little copper wire into the under jaw of 



Fig. 79. Position of Pollack Whiting for casting. 



Fig. So. Ballan Wrasse, with fins spread out, ready for casting. ' 



the mould. Both mould and cast must be put away j 

 for a day or two, after which the task of taking off 

 the mould may be commenced. 



Perhaps, in setting, the heat of the larger quantity 

 of plaster which has been employed in making the 

 cast will have cracked the mould. If so, it is ad- 

 vantageous, for each mould can only be used once ; if 

 the fish operated on be a rare one, it is best, there- 

 fore, to take several moulds of it. Of course, a good 

 deal depends on the shape of the fish as to how it 

 shall be extracted from the mould. In the flat-fishes, 

 as the sole, turbot, brill, halibut, flounder, and 

 skates, there is little difficulty. By inserting the 

 edge of a knife between the mould and the cast, the 

 former will come off. Most fishes are laid on their 

 sides when the mould is being made, as, for instance, 

 perch, bream, roach, pike, cod, mackerel, salmon, 

 &c. ; but such triangular-bodied fish as the gurnard, 

 coitus, &c, had best be placed with the belly side 

 downwards, and their large pectoral fins spread out. 

 Sometimes it will be necessary to break off the mould 

 in pieces, and much care and patience will then be 

 required. But experience in manipulation comes after 

 a few trials, and it is astonishing how soon we learn 

 to proceed under all circumstances. 



Fig. Si. Butterfly Blenny, showing expanded dorsal fin. 



Fig. 82. The Piper Gurnard (Trigla lyrii), showing separate 

 rays of pectoral fins. 



Fig. S3. 



Three-bearded Rockling, showing barbels on mouth, 

 which have to be imitated with wire. 



the cast, and then covering it with a mixture of gum- 

 water and plaster of Paris, laid on with a small camel- 

 hair brush. The loose, leg-like rays of the pectoral 

 fins of the Gurnard may easily be imitated in a 

 similar way. We always like to see the dorsal, 

 caudal, pectoral, and other fins laid out, so that the 



