8 SCIENTIFIC AMUSEMENTS. 



by mixing alum-water with the plaster of Paris in first preparing 

 the " slip " for the casting. 



Clay tobacco-pipes are prepared after a somewhat similar fashion. 

 A long thin piece of clay is rolled out and a wire carefully threaded 

 through it \ this is placed in that part of a hinged mould that is 

 to form the stem ; some more clay is placed in the adjoining part 

 of the mould forming the bowl, and a well-oiled solid metal plug 

 forced in so as to produce the hollow of the bowl, and join it on 

 to the stem ; the plug and wire being then withdrawn, the mould 

 is opened and the soft clay shaped into a pipe removed and set by 

 to dry and harden; after which it is baked to complete the 

 operation. 



Expt. 4. To mould a Human Hand. In order to take a cast 

 of a friend's hand or foot, a piece of flat board should be provided 

 with the upper surface well oiled ; the hand to be modelled is 

 also oiled, and then held so as to rest lightly on the board, palm 

 downwards. Plaster slip is then poured over the hand, and when 

 a thin coating has been formed, two or three pieces of stout tape 

 are placed over this coating with the ends projecting outwards 

 some inches. More slip is then poured over the coating so as to 

 imbed the tapes firmly in the resulting mass, and the process 

 continued until the mould is sufficiently thick. When the plaster 

 has thoroughly set, the whole mass is gently lifted up by means 

 of the tapes, and detached from the hand, care being taken not to 

 break or crack the mass whilst liberating the fingers and thumb. 

 In this way a mould of the hand is obtained from which an exact 

 copy of the hand itself may be prepared by thoroughly drying the 

 mould and well oiling it (see Expt. 3), and then turning it upside 

 down and filling the cavity with fresh slip, to which (if required) 

 a little vermilion or rouge or carmine-lake may be added so as to 

 give a light red or pink tint ; whilst this slip is setting a piece of 

 tape is thrust into it, so that when completely solidified the mould 

 and cast may be separated from one another by gently pulling the 

 tapes. 



Caution. Do not attempt to take a cast of the face in this 

 way ; in the first place there is very great danger of stifling the 

 subject by plugging up the mouth and nostrils so as to render it 

 impossible to breathe ; and in the second place, unless the forehead 

 and eyebrows, and in the case of a gentleman the whiskers and 

 moustache, be cut very short or shaved, it will very probably be 

 impossible to detach the cast on account of the hairs being im- 

 bedded therein, in which case the plaster would have to be cut 

 away by means of a chisel. 



Expt. 5. To make a Wax Lemon. Cut a lemon in two halves 



