CLAY WORKING INDUSTRIES. 367 



The cost of the additional labor and handling required by this method 

 of drying must be included as a part of the expense. In fact, all of the 

 systems of drying in use, are so connected with the means of getting 

 the brick into and out of the drying plant, that the mere cost in fuel and 

 attendance cannot be given as a fair statement of the cost of the method. 



Sewer Pipe Floors. Sewer pipe is an article which it is very diffi- 

 cult to dry safely and fire proofing is still more troublesome and hence 

 those engaged in this line of work have perfected a system of drying 

 which, when applied to bricks, forms the safest and least objectionable 

 plan that can be used. However, it entails the use of a very expensive 

 plant, especially if the quantity to be dried daily is large. 



The plan of operation is to expose the wares, piled in open order 

 two or four deep on slatted or open floors, to the gentle heat and soft air 

 currents caused \>y steam pipes placed in open order underneath the 

 floors. The piping is generally applied under the two lower floors, and 

 the warm air from below is sure to rise and assist in drying the wares 

 above. The steam is supplied during the day time by the exhaust of 

 the steam engines and steam presses if they are used. During the night, 

 the use of a small amount of live steam is necessary especially in cold 

 weather. 



The principle of this process is the absorption of the moisture o 

 the bricks by simple exposure to warm air. No effort is made to pro_ 

 duce air currents and the heat used is usually quite small and cannot be 

 made high without great cost for extra piping and use of live steam. 

 The cost of the process is most manifest in considering the expense of 

 fitting up to use it. 



The ordinary period of exposure is about seven days for paving 

 blocks. It can be managed with less time, but seven days is the least 

 time to do the work with the attainment of great economy. 



To get floor room capable of holding an output of 30,000 per day 

 and allowing seven days for drying, requires a large, tall and strong build- 

 ing, as aside from the weight of the machinery, the weight on the floors 

 will run from 600 to 1,000 tons. 



The labor involved in the use of this process is just the same as in 

 the dry floor ; the material all has to be put down and taken up by hand 

 and in addition, the large area of floors occupied by bricks and the num- 

 ber of stones generally used, cause extra expense in getting the material 

 down to the kiln yard after it is dry. 



The character of the drying done in this way is the safest, best and 

 most wholesome that can be obtained; there are no violent changes in 

 temperature, or forcing of natural conditions at any point. 



The cost of drying by this process after the building and piping are 

 once in operation is very little. Many brickmakers dry during 9 months 

 of the year at absolutely no expense whatever for fuel, which would not 



