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This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This page directs the use of hazardous substances — such as benzine, gasoline, lye, or strong acids — for household tasks. These materials are highly flammable, corrosive, or poisonous, and the practices described have caused fires, burns, and poisonings.
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Adhesives, Paints, and Varnishes: Fish
To Purify Fish Oil.-Make for this purpose a bag of any coarse cloth, as burlap or canvas, line it with flannel, and put in between the bag and the lining a layer of charcoal inch thick.
The bag should be quilted to keep the charcoal in place. Pour the oil into this filter and let it run into a leadlined vat containing water to the depth of 5 or 6 inches, slightly acidulated with blue vitriol. Let stand 3 or 4 days, and draw off the oil by means of a spigot fixed slightly above the level of the water. Repeat if necessary. Finally filter through cloth bags without charcoal into tanks or barrels for storage.
To Deodorize Putrid Fish Oil. - For each 100 pounds of oil, pulverize 1 pound of chloride of lime; rub to a stiff paste with a little cold water, and thin to the consistency of cream. Pour the oil into a lead-lined vat, stir in the chloride of lime, and let stand 3 or 4 hours, stirring frequently.
Add 1 pound of sulphuric acid diluted in 25 times its volume of water, and boil in an iron kettle on a slow fire, stirring constantly. When the mixture is perfectly liquid and falls in drops from the stirrer, return to the vat, and when the oil has separated, draw off the water by means of a spigot.
To Preserve Animal Oils. - Add 1 dram of powdered slippery-elm bark to each pound of oil, and heat gently over a slow fire. When the bark settles, strain off the fat. This gives an agreeable odor to the oil and prevents it from becoming rancid. To Restore Rancid Animal Oils.- Put the oil in a suitable kettle over a slow fire, and stir in clean lumps or grains of charcoal from which the dust has been removed by winnowing with fans.