ECONOMIC OPERATION OF CREAMERY. 331 



The following comparative table is given by Kent: 



Hickory or hard maple, weight per cord 4500 Ibs. = 1800 to 2000 Ibs. of coal. 

 White oak " " " 3850 " =1540 to 1715 " " " 



Poplar, chestnut and cedar " " " 2350 ' ' = 940 to 1050 " " " 

 Pine " " " 2000 " = 800 to 925 " " " 



Whether a creamery can economically use slack or lump 

 coal is another question worth considering. Slack coal is used 

 very little in local creameries, first, because it is more difficult 

 to use in firing. Usually help is scarce, and coal which requires 

 less attention in firing than slack, is preferred. Second, slack 

 coal is subject to spontaneous* combustion and likely to set 

 buildings afire. Some, if not all insurance companies, dis- 

 criminate against creameries using slack coal as fuel. Third, 

 special grates (rocking grates) are essential to get best results 

 from using slack. Fourth, slack coal is dirty and the dust 

 from it will lodge all over in the boiler and engine room. 



Slack coal, where conditions are at all favorable for its use, 

 is, as a rule, cheap to burn. According to experimental data, 

 1 pound of slack coal will produce about 4 pounds of steam, 

 and 1 pound of lump coal will produce about 6 pounds of 

 steam. The price of the two will vary, but usually the rela- 

 tion is, slack coal, $1.25 per ton; lump coal, $3.25 per ton. 

 If 1 pound of lump coal produces 6 pounds of steam, a ton 

 will produce 12,000 pounds. If 1 pound of slack coal produces 

 4 pounds of steam, to produce 12,000 pounds will require 

 2992 pounds of slack coal, which would cost $1.87. The 

 difference in producing 12,000 pounds of steam in favor of 

 slack coal would then be $1.38. 



Daily Weighing of Coal Used. The advantage of daily 

 weighing of coal used in creameries cannot be too strongly 

 emphasized. That business phase of creamery work has been 

 much neglected in the past. If the coal used daily is not 

 weighed, a serious loss or leak may continue without detec- 

 tion. Firing the boiler is a daily occurrence, and if a small 

 loss occurs, the total loss at the end of the year would cut 

 short the profits. 



