ARTIFICIAL STONE, OR CONCRETE 



such machines are too expensive for most builders. 

 The usual method of feeding the mixers is by shoveling 

 obviously one that is likely to be very inaccurate. 

 Some ingenious contractors, however, find a way of 

 using shovels as very accurate measurers. If the mix- 

 ture they wish to use consists of one part cement, two 

 parts sand, and three parts gravel, they place three 

 shovelers at the gravel pile, two at the sand pile, and 

 one at the cement pile, each supplied with shovels of 

 exactly the same size, so made that they will take up 

 practically the same amount of material at each scoop 

 of an average workman. By having these six men 

 shovel in unison they are able to supply the mixing 

 machine with the materials in proportions accurate 

 enough for all practical purposes. 



MOLDING THE BLOCKS 



For molding the concrete into blocks, mixtures of 

 three consistencies are used, known as dry, medium, 

 and wet mixtures respectively. The dry mixture is 

 not dry in the strict sense, but is of a consistency too 

 stiff to be poured; the wet is thin and pours readily; 

 while the medium is intermediate between the two. 

 The molds used may be of any desired size or shape, 

 and are sometimes made of sand in much the same 

 manner as molds for iron-casting. More frequently 

 they are made of iron or wood, so arranged that the 

 sides are jointed to facilitate the removal of the block 

 when it has set. 



When a dry mixture is used, this is shoveled into 



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