Place 4 grams of the sample in a 200-cc. flask, add water to the mark, and allow the mass to infuse for eight hours, with occasional shaking; let stand 16 hours longer without shaking, filter, evaporate 50 cc. of filtrate to dryness in a flat-bottomed dish, dry at 100 deg. C., cool and weigh. 7. _Ash--Official_ Char a quantity of the substance, representing about 2 grams of the dry material, and burn until free of carbon at a low heat, not to exceed dull redness. If a carbon-free ash can not be obtained in this manner, exhaust the charred mass with hot water, collect the insoluble residue on a filter, burn till the ash is white or nearly so, and then add the filtrate to the ash and evaporate to dryness. Heat to low redness, until ash is white or grayish white, and weigh. 8. _Ash Insoluble in Acid--Official_ Boil the water-insoluble residue, obtained as directed under 9, or the total ash obtained as directed under 7, with 25 cc. of 10-percent hydrochloric acid (sp. gr. 1.050) for 5 minutes, collect the insoluble matter on a Gooch crucible or an ashless filter, wash with hot water, ignite and weigh. 9. _Soluble and Insoluble Ash--Official_ Heat 5 to 10 grams of the sample in a platinum dish of from 50 to 100 cc. capacity at 100 deg. C. until the water is expelled, and add a few drops of pure olive oil and heat slowly over a flame until swelling ceases. Then place the dish in a muffle and heat at low redness until a white ash is obtained. Add water to the ash, in the platinum dish, heat nearly to boiling, filter through ash-free filter paper, and wash with hot water until the combined filtrate and washings measure to about 60 cc. Return the filter and contents to the platinum dish, carefully ignite, cool and weigh. Compute percentages of water-insoluble ash and water-soluble ash. 10. _Alkalinity of the Soluble Ash--Official_ Cool the filtrate from 9 and titrate with N/10 hydrochloric acid, using methyl orange as an indicator. Express the alkalinity in terms of the number of cc. of N/10 acid per 1 gram of the sample. 11. _Soluble Phosphoric Acid in the Ash--Official_