Excerpt from Cooperative Work on the Titer Test, Association of Official Agricultural Chemists, 1904
Redissolve in 20 cc of alcohol and again dry to a condition in which the soap will not adhere to the spatula by pressure.
Transfer the dry soap to the porcelain dish.... Add 1 or 2 liters of boiling water and keep the mixture boiling for 40 minutes. Replace, by adding cold water, about the same quantity of water which has been evaporated by the previous boiling. Add to the soap solution 70 cc of 25° Baumé sulphuric acid. Boil again until the fatty acids, which will ¿oat on top, are perfectly clear and transparent and show no signs of any particle of soap which has not dissolved. Siphon off the acid water and trans fer the fatty acids to a small beaker, melt the acids, and allow the water to settle; transfer to a dry beaker and dry in a water bath or on a steam bath for 20 minutes and filter the fatty acids through white filter paper, using a hot-water funnel.
Place the clear fatty acids in the titer tube, filling it two-thirds full, the tube being first warmed in the water bath. Insert the tube in the perforated cork of the large bottle, to serve as an air bath, and hang the delicate thermometer so that the bulb will be exactly in the middle, in all directions, of the mass and allow the fatty acids to cool until the mercury stops falling and just begins to rise again. Then move the thermometer rapidly around the sides of the tube, three times to the right and three times to the left, without any up or down motion, finally replacing the thermometer in the center of the tube.
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