684 Transactions of the American Institute. 



Dr. L. Feuchtwanger stated that Ransom's stone bad been much 

 improved lately, and did not now absorb moisture. He employs an 

 immense pressure after applying the chloride of calcium, and after 

 that pressure the stone is steamed. 



The President — An artificial stone containing Portland cement is 

 like the old-fashioned receipt for making stone soup, the virtue not 

 being in the stone, but in the meat that went with it. The virtue is 

 not in the so-called improvements, but in the original hydraulic cement 

 which nature has provided. 



Mr. Harniepell considered Dr. Ott's artificial stone an improvement 

 on those heretofore produced, arising from its semi-crystalline struc- 

 ture. Slags are produced of great hardness, but they are extremely 

 brittle. But this stone combines the hardness with toughness. 

 Granite is a conglomerate stone, of coarse structure, but a valuable 

 stone for building ; but in Dr. Ott's stone, which appears to be a 

 species of conglomerate, the structure is much finer. It is not 

 alkaline in its nature. The absorption of water is fully provided for ; 

 and there is nothing to produce the porosity which exists in some 

 other stones. 



The President — There is an entire absence of silicate of alumina. 

 And there should be no water of crystallization in cement stone for 

 ordinary buildings. 



Dr. A. Ott — In hydraulic cements, as in all artificial stone, there is 

 water chemically combined with it. It unites with the cement when 

 it is used. 



The President — That would not stand a fire. 



Dr. A. Ott — The water can be expelled at a very high temperature. 

 At the late fire in Chicago, the buildings of artificial stone stood the 

 fire better than those of natural stone. 



Dr. D. D. Parmelee — If it withstands fire, it does not contain 

 water. 



The President — Chemists should understand that what is wanted 

 is not artificial stone, but something to take the place of Rosendale 

 cement, of which 1,000 barrels a day are sent to the market. 



Dr. A. Ott — The Rosendale cement is very inferior to the im- 

 ported cements. It is unfit to be used for pavements. A good 

 cement should be of a light gray color, with a greenish or bluish 

 tinge, but never of a rusty color. But what is the use of searching 

 for deposits of natural cement, when from the elements of lime, silica 

 and clay, we can not only produce a cement superior to the best 



