STATE GEOLOGIST. 219 
uniform surface between the stakes, and as the concrete is placed upon the 
sub-grade it must be regulated with shovels by skilled labor to conform to the 
grade immediately upon its emplacement, and then rammed or tamped suffic- 
iently in place to form a solid and compact mass. The labor necessary to spread 
and compact the concrete must be other than that required to mix it. In com- 
. pacting the material in place the operation of ramming or tamping must be 
continued until the top surface is regular and the water in the mass begins 
to appear on the surface. No mortar that has been prepared for the purpose 
of forming a new batch of concrete shall be taken to plaster any rough or 
improperly tamped places that may appear in the base, as ramming or tamp- 
ing must be the only means employed to obtain a smooth and regular surface. 
The removal and placing of the concrete to grade should be performed in 
such a manner as not to disturb the uniformity of the mixture. 
Any lack of compaction or evidence of inferior setting in the base will 
be sufficient reason to require its removal and new concrete substituted for it. 
If required, the earth in the sub-grade will be dampened before the con- 
crete is laid, and the concrete base shall be sprinkled and wetted as often 
as required during dry or hot weather to prevent damage from too rapid 
evaporation, etc. 
No cement concrete base shall be laid during very cold or freezing weather 
without permission of the Engineer Commissioner and then only under sucn 
special regulations and instructions as he may think necessary. 
No hauling must be done over or upon the base, for any purpose until 
after it shall have sufficiently set to withstand fracture, and, if necessary, 
the base shall be planked before any hauling is done. 
