Manufacture and Builder 6, 1879
The following is a good recipe.One quart of shellac dissolved in alcohol, 3 ounces of pulverized pumice stone, 2 ounces of pulverized rottenoturie, and 4 ounces of lampblack; mix the last three ingredients together, moisten a portion at a time with a little of the shellac and alcohol, gringd as thoroughly as possible with a knife or spatula, after which pour in the remainder of the alcohol, stirring often to prevent settling. One quart will furnish two coats for 8O square feet of blackboard not previously painted. The preparation dries immediately, and the board may he used within an hour if necessary. For further information we refer you to the the answer to Query 1105, entitled "Liquid Slate for Blackboards," on page 261 of our November number for 1974.
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