322 COX, REIBLING, AND REYES. 
promoters and manufacturers. Such practises serve to destroy 
the confidence of the financier, architect, and general public, and 
their object lesson is one which must be heeded. A competition 
for cheapness and not for quality is the most frequent and cer- 
tain cause of failure. 
Michaelis permitted the letters patent on this process of harden- 
ing by superheated steam to lapse without commercial application, 
and therefore it is public property. No secret formulas or chem- 
icals are necessary, and, if the available raw materials are satis- 
factory, manufacturers are willing to enter into contract to 
furnish working drawings and blue prints for the necessary 
foundations and buildings, equip and install the machinery, and 
put the whole plant in proper operation. There are a few 
patents concerning the economy of manufacture which have 
more or less merit, but recently an all-American system with 
no patents has been introduced. 
MIXED CARBONATE AND SILICATE BINDER. 
A combination of the two hardening processes just described 
provides for the introduction of carbon dioxide from the lime 
kilns and steam into closed iron chambers. The binding material 
formed at atmospheric pressure is mainly calcium carbonate. 
The amount of calcium silicate formed increases with the steam 
pressure, while that of the carbonate decreases. 
Peppel * believes that sand bricks with a silicate bond are the 
only ones which will ever take any important place in the 
world’s markets, but an inspection of the works and products of 
the British Stone and Marble Co., Ltd., Ponders End, Middlesex, 
England, gives an entirely different impression. This company 
uses and claims to own a process whereby the débris of any suit- 
able building stone is first reduced by mechanical disintegration 
to a granular state and: then built up again into stone practically 
indistinguishable from the quarried product. As its trade name 
indicates, it is “reconstructed stone.” The characteristic fea- 
tures of the natural product are produced with accuracy while 
the defects are eliminated. The process consists in disintegrat- 
ing quarry débris without destroying the form of the original 
component grains, mixing the resultant grit with a definite pro- 
portion of lime calcined in closed retorts, slaking the mixture 
thoroughly, and, after the addition of considerable water, con- 
solidating under great pressure into blocks of any desirable size 
* Loc. cit. 
