ARTIFICIAL STONE, OR CONCRETE 



in the crystallization of the silicates of aluminum and 

 lime. 



This curing process is the most tedious of all those 

 involved in concrete-block construction, and un- 

 fortunately, the one that is most likely to be slighted. 

 Blocks made by the dry process must be cured by 

 repeated sprayings with water for a period of from ten 

 to twenty days, during which time they should not 

 be allowed to become dry ; and blocks made of medium 

 concrete require a proportionate time for the curing. 

 For the chemical process which results in fine concrete 

 is a slow one, unless hurried by heating, or some other 

 expensive process. It is a strong temptation to the 

 block- maker, therefore, when his customers are chafing 

 at what must seem needless delay, to curtail the curing 

 process. Blocks so slighted may have every appear- 

 ance of being first class, and only the crumblings 

 wrought by the atmosphere a few years later reveal the 

 folly of the block-maker. Folly, I say, as well as cul- 

 pable negligence, since it is this and similar short- 

 sighted actions on the part of the concrete-block maker 

 in the past that have shaken the confidence of builders, 

 and retarded the general introduction of concrete 

 blocks as building material. Had honesty in the use 

 of material, and care in the process of block manu- 

 facture been exercised in the past, the concrete -block 

 industry would long since have assumed the enormous 

 proportions that the usefulness of this material merits. 

 It is just now coming into its own, through the efforts 

 of manufacturers who have proved their claim to 

 honesty. 



