Dissolve 1 gram of the sample and dilute to 200 cc. with freshly boiled
distilled water cooled to 30° C. or less. Add 5 cc. of dilute sulfuric
acid (1 to 3) to a 50 cc. portion of the solution and titrate with N/10
potassium permanganate. The percentage of ferrous sulfate
(FeSO_{4}.7H_{2}O) is equal to 11.12 times the number of cubic
centimeters of potassium permanganate used.