THE REP ROD UCTION OF FISHES FROM GL UE MO ULDS 24 1 



practicable, and indeed advantageous, to rest the object upon 

 the heads of three nails driven into a piece of board. 



This method dispenses with two tiresome and lengthy pro- 

 cesses, namely, coating the specimen with clay and making a 

 " jacket '' of plaster. 



There is certainly nothing half so safe as the modelling-glue 

 of which to make a mould from a delicate or undercut fossil, 

 where a plaster mould would be of no avail, and might break 

 the specimen, even if not undercut, and where wax and gutta- 

 percha would do the same, or stick and refuse to come away. 

 The good modelling-glue (Formula 96), which must always be 

 used for delicate specimens, will perfectly relieve, and come 

 away sweetly, without the slightest danger, from a slightly 

 oiled fossil. 



In all cases the glue mould must be thinly painted, or, 

 better still, varnished — care being taken not to fill up any 

 sculpture — before the plaster is poured into it 



To cast a Fish in Plaster from a Glue Mould 



The fish, being laid upon the board and prepared for 

 casting as before described, is dried by gently patting it with 

 a soft cloth. It is then oiled all over, but with only just suffi- 

 cient oil to damp it and not to flow over it. When all is ready, 

 pour over it a thin coating of the glue composition. Formula 95, 

 followed by another, and so on, until a fairly thick glue mould 

 is obtained, the crucial part of the operation being not to have 

 the composition too hot, nor, indeed, so hot as is required for 

 making a model in the ordinary way, and letting each coat, 

 subsequent to the first, grow colder by trickling on the half- 

 warm glue. Set the board with its contents out in the air, if 

 possible, to cool, which takes about an hour. When it is cool 

 enough, give the glue mould — without moving anything in the 

 least or turning it over — a coating of thick white paint with 



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