64 ANNUAL REPORT 
These men may be unskilled laborers, but with a skilled foreman to direct, 
the work can be of the best quality. 
It requires from one-eighth to one-third of the time to place a con- 
crete foundation that it requires to construct one of stone. Within thirty- 
six hours after the completion of the concrete foundation, work upon the 
superstructure may proceed. 
Those that know little about concrete may question its one 
For their benefit attention is called to the durability of concrete as illus- 
trated in the historical portion of this paper. Portions of the Cartha- 
gvenian aqueduct are intact after 2,000 years of weathering. The dome 
of the Pantheon still survives the ravages of 2,000 years. In 1892, while 
excavations were being made in London, workmen came upon a heavy 
mass of natural cement concrete laid over 800 years ago. Blasting was 
out of the question, owing to the proximity to other buildings. So 
workmen were employed to cut out the concrete with chisel and hammer. 
The. concrete was so hard that it turned the best steel tools. 
In 1872, J. V. Farwell erected a large store at the corner of Market 
and Franklin streets in Chicago, with foundations and interior walls of 
natural cement concrete. The building is still used for mercantile pur- 
poses with the concrete portion apparently as perfect as ever. Another 
of Farwell’s buildings, erected in 1869, was in the path of the great 
Chicago fire of 1871. While the interior partitions of wood were burned 
out, the walls of concrete stood, so that within a very short time the 
building was repaired and was used by the Government for court, 
treasury and customs offices. 
The United States Government in erecting the postoffice building 
in Chicago, in 1872, built it upon a cement foundation slab several feet 
thick extending under the entire building. In 1897 that building was 
torn down to make room for the new Federal building recently completed. 
The contractor was compelled to use steam drills and dynamite to remove 
the concrete, and because of its refractory nature was so delayed in 
finishing his work, that it entailed the payment by him of a penalty of $100 
per day for several weeks. ‘With such a record for natural and “Roman” 
cements, greater results may be expected from the more perfect Portland 
cements. 
HEAVY CONSTRUCTION. 
From footing courses and foundation walls to abutments, retaining 
walls and heavy superstructure was but a step. 
These are constructed both of massive concrete blocks and in mono- 
lithic form. 
WALLS. 
In the construction of the Consolidated Lake Superior Power Co.’s 
plant at Sault Ste. Marie, Mich., immense concrete blocks with mortised 
