Breakdowns. In laying out and setting up a mixing 

 plant, always anticipate the inevitable breakdown, and 

 its effect on the progress of the work. In a case of 

 breakdown of the feeding machinery, have an auxiliary 

 supply of material available. In case the mixer breaks, 

 have a mixing board ready and if necessary keep the 

 work going by hand. 



Feeding the Mixer. We cannot too strongly urge 

 more exact and positively accurate methods of feeding 

 the mixer. A few years ago, our "best" methods were 

 hardly better than guess work, and the results depended 

 entirely upon the intelligence and constant vigilance of 

 the "man behind the mixer." It will pay any man in 

 the field to keep in constant touch with the new devel- 

 opments in this line, which is easily done through the 

 medium of the trade publications. Send for these and 

 study them, for the machinery described usually repre- 

 sents the very latest, the "last words," as it were, on 

 this matter. 



Wheelbarrow Measurements. Do not depend on 

 wheelbarrow measurement to establish your propor- 

 tions of sand and slag, for that is little more than 

 guess work. It is far better to enter the sand and 

 slag into separate compartments of a hopper, the divi- 

 sion slide of which can be adjusted to meet different 

 grades of material, then adding the proper amount of 

 cement, usually determined by the number of sacks of 

 I cu. ft. each, to place this entire batch correctly pro- 

 portioned and carefully checked, into the mixer at one 

 operation. 



Measuring sand and stone by wheelbarrows is an 

 inaccurate approximation. If it must be done, make a 

 cube box without a bottom along the same line as pre- 

 viously mentioned, only small enough to get in a bar- 

 row and of an exact size to contain when struck, a 

 specified number of cubic feet. Place this form on the 

 barrow, fill it to a struck surface, remove the frame 



