DAILY WEIGHING OF COAL USED 383 



The following comparative table is given by Kent: 



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

 White oak, weight per cord 3850 Ibs. = 1540 to 1715 Ibs. of coal. 



Poplar, chestnut and cedar, weight per cord 2350 Ibs. = 940 to 1050 Ibs. of coal. 

 Pine, weight per cord 2000 lbs.= 800 to 925 Ibs. of coal. 



Whether a creamery can economically use slack or lump coal 

 is another question worth considering. Slack coal is used very 

 little in local creameries, mainly because it is more difficult to use 

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

 attention in firing is preferred. In the second place slack coal is 

 subject to spontaneous combustion and likely to set buildings 

 afire. Some, if not all insurance companies, discriminate against 

 creameries using slack coal as fuel. Thirdly, special grates 

 (rocking grates) are essential to get best results from using slack. 

 Fourthly, 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, 

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

 and i pound of lump coal will produce about 6 pounds of steam. 

 The price of the two will vary, but usually the relation is, slack 

 coal, $1.25 per ton; lump coal, $3.25 per ton. If i pound of lump 

 coal produces 6 pounds of steam, a ton will produce 12,000 

 pounds. If i 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 detection. Firing 

 the boiler is a daily occurrence, and if a small loss occurs, the total 

 loss at the end of the year will cut short the profits. 



The weighing can be done conveniently by fitting a box 

 similar in shape to an enlarged flat-sided curd pail on a pair of 

 platform scales. After the scale and box have been purchased 



