STATE GEOLOGIST. 17 
CHAPTER I. 
A BRIEF HISTORY OF CEMENT. 
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Cummings in his “American Cements” says: “The fact is, the his- 
tory of natural rock cement reaches so far back into the early ages, that - 
it is impossible to learn precisely the date of its earliest fabrication. But 
we do know that ancient Egyptians made natural cement 4,000 years ago, 
which set under water. The Romans over 2,000 years ago used it in 
sewer and water mains, fountains, etc. Prior to this an aqueduct over 70 
miles in length was built for the ancient city of Carthage. At one place it 
was catried across a valley on arches over 100 feet high, 1,000 arches in 
the line. Immense quantities of natural cement were used in its con- 
struction. Some of these arches are still standing. At one point where 
the arches are the highest, a piece over 100 feet long has fallen from the 
top of the aqueduct to the rocks below and still lies there intact, unbroken, 
illustrating the toughness, tenacity and durability of the natural rock 
cement.”’ : 
Shadwell in “The Architectural History of the City of Rome” says 
that the earliest use of lime mortar among the Romans dates back to 175 
B. C. to the construction of the “Emporium,” the walls of which are a 
mass of concrete, rough stone and mortar. Irom this time on much con- 
crete was used in the walls of buildings, fortifications, aqueducts, etc. 
The Colosseum, built by Vespasian and Titus, A. D. 75 to 80, was 
largely of concrete walls with cut Travertine stone, having the inner walls 
faced with brick. 
The aqueducts, in order to make them impervious, were lined with 
a cement mortar composed of crushed fragments of brick with fresh lime, 
called by the early Romans, “Opus signinum;” it is still known and used 
in Rome under the name “‘cocciopesto.”’ 
Another form of concrete known as “Opus Reticulatum,” looks like 
brick work, but is composed of a lime concrete wall having wedge shaped 
pieces of Tufa driven into the face of the wall before the concrete attained 
full set. It is said that some 25 or-30 years ago an attempt to destroy 
such a wall on the Quirinal, failed on account of the immense expense 
required due to the extreme hardness and toughness of the concrete, such 
walls being indestructible except by the use of dynamite. 
2—s. G. 
