PANDA ANNUAL REPORT 
39. Large Stone.—The incorporation into the concrete of clean, hard, 
sound stones, roughly scabbled and of all sizes that may be conveniently 
handled over 50 lbs. weight, will be permitted, provided the stones be sep- 
arated by a minimum thickness of 4 inches of concrete, and be thoroughly 
imbedded in the concrete on every side. Such stones must be thoroughly 
scrubbed clean before being placed in the work and shall be wetted immediately 
before setting in position. At least 30 per cent. of the entire mass may 
consist of stones so embodied in the work. Any stones considered unsound 
or unsuitable by the engineer shall be immediately removed. | 
40. Ramming, —The rammers for the facing shall be of iron or steel with 
flat rectangular faces 14%, inches by 4 inches. They shall be 5 inches long 
with solid steel handles. The operation of ramming must give a thoroughly 
compacted dense, artificial stone of high specific gravity. When deficiency of 
moisture is indicated after ramming is completed, it will be supplied by 
sprinkling with a fine spray of water. All exposed surfaces of unfinished 
work will be kept constantly moist by sprinkling at short intervals. For this 
purpose not less than one large watering pot for each mixer will be kept in 
constant service, and aS many more as may be required. 
4J, Water Tank,—The contractor will be required to provide a tank of 
10,000 gallons capacity, at a height of 50 feet above top of dam, keeping the 
same well filled and connected with hose for the frequent and practically con- 
tinuous sprinkling of the finished work. 
42, Surface to be Cleaned and Roughened,—Rock surfaces, and concrete 
surfaces more than twenty-four hours old, shall be mopped with a mixture 
of neat Portland cement mortar immediately before the application of a fresh 
course of concrete, and all surfaces to which mortar or concrete is applied 
shall be made clean from any dirt, sand, clay or foreign substances and care- 
fully roughened by picking before the application of such mortar or concrete. 
Under no circumstances will any concrete be laid in water or in freezing 
weather. 
43, Concrete Forms, —Concrete forms must be rigidly held in position 
so as to give accurately the exterior surface required by the plans for the 
work, being secured against yielding to the operation of ramming. Surfaces 
of planking forming exterior faces must give the true, plane surface or 
curved surface required for the walls, and shall be dressed to make the 
planks of a uniform thickness. The price bid per cubic yard for concrete 
in place shall include all lumber, timber, bolts and materials used in the 
forms for the concrete. Also all special molds for ornamental arches, out- 
line of imitation range work on lower faces as shown by the plans and all 
pick facing to remove mold marks, and give the exterior face of wall the 
appearance of cyclopean masonry indicated on the drawings. 
44, Cement, —The contractor will be required to provide a suitable build- 
ing, heated when necessary, to maintain the proper temperature, for testing 
~ cement, and also the necessary labor for handling the barrels or packages 
and taking the samples for testing purposes. Cement must be on hand 
for testing in time to complete all tests before the cement is required for use 
in the work, which shall not be more than ten days. It is to be stored in dry, 
well ventilated buildings, and protected from deterioration. It may be rejected 
for such deterioration, after passing the required tests. Cement must be 
stored by carload lots for ready removal of any lot condemned. It must be 
stored in strong packages, well lined with paper, so as to be reasonably 
secure from air and moisture. Each package to be labeled with the name of the 
