The yearly variation shows but little change, as the average cost per ton was for 1893, $4.75; for 1894, $3.99; for 1895, $4.21; for 1896, $3.90. In considering the total cost of refining, the additional factors of interest, expressage, parting, brokerage, and reworking of by-products must be considered. As the doré silver is treated at the works or elsewhere, so will the total cost be less or greater. The following table gives the cost in detail, when the parting is done at the same works: AVERAGE MONTHLY COST OF REFINING PER TON OF BULLION TREATED ─────────────────────┬────────────┬────────────┬────────────┬───────── ITEMS │ 1895 │ 1895 │ 1896 │ AVERAGE │JAN. TO JULY│JULY TO DEC.│JAN. TO JULY│ ─────────────────────┼────────────┼────────────┼────────────┼───────── Labor │ $2.351 │ $1.718 │ $1.836 │ $1.968 Spelter │ 0.757 │ 0.840 │ 0.987 │ 0.861 Coal │ 0.585 │ 0.442 │ 0.461 │ 0.496 Coke │ 0.634 │ 0.418 │ 0.511 │ 0.521 Supplies, repairs and│ │ │ │ general expenses │ 0.343 │ 0.273 │ 0.252 │ 0.289 Interest │ 1.808 │ 1.075 │ 1.070 │ 1.317 Expressage │ 1.360 │ 1.015 │ 0.882 │ 1.085 Parting and brokerage│ 2.483 │ 2.084 │ 1.796 │ 2.121 Reworking by-products│ 1.567 │ 1.286 │ 1.625 │ 1.492 ├────────────┼────────────┼────────────┼───────── Totals │ $11.888 │ $9.151 │ $9.420 │ $10.151 Tons bullion refined │5,511.58 │9,249.07 │10,103.43 │8,287.99 ─────────────────────┴────────────┴────────────┴────────────┴───────── An analysis of the different items of cost is important, and a brief summary is given below. _Labor and Attendance._—The cost for this item varies but little from year to year, and its reduction depends, for the most part, on a larger yield per man rather than on a reduction of wages. If a man at the same or slightly increased cost can give a larger output, so will the labor cost per ton be diminished. This result is accomplished by enlarging the furnace capacity and by using appliances which will handle the bullion and its products in an easier and quicker manner. The small size of the furnaces, settlers and retorts used at modern refineries is open to criticism; I believe that great improvement can be made in this direction. _Spelter._—The cost of this item varies with the market conditions, and will probably be changed but little in the future, as the amount necessary per ton of bullion seems to be fixed.