Bulletin - Bureau of Chemistry, Issues 35-40

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U.S. Government Printing Office, 1892 - Agricultural chemistry
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Page 171 - Keep the mixture in a warm place for several days, or until a portion heated to 40" C. deposits no yellow precipitate of ammonium phosphomolybdate. Decant the solution from any sediment and preserve in glass-stoppered vessels.
Page 169 - C., drop into it the filter containing the washed residue from the water-soluble phosphoric acid determination, close tightly with a smooth rubber stopper, and shake violently until the filter paper is reduced to a pulp. Place the flask in the bath and maintain it at such a temperature that the contents of the flask will stand at exactly 65 C.
Page 190 - To this residue, in a 500 cc flask, add 200 cc of boiling 1.25 per cent. sulphuric acid ; connect the flask with an inverted condenser, the tube of which passes only a short distance beyond the rubber stopper into the flask. Boil at once, and continue the boiling for thirty minutes.
Page 201 - Next add 50 cc of the soda solution, or sufficient to make the reaction strongly alkaline, pouring it down the side of the flask so that it does not mix at once with the acid solution. Connect the flask with the condenser, mix the contents by shaking, and distil until all ammonia has passed over into the standard acid. The first 150 cc of the distillate will generally contain all the ammonia.
Page 217 - Cover the crucible containing the residue from the fat determination by the indirect method (see 4 (a) ) and heat gently at first, gradually raising the temperature to just below redness. The cover may then be removed and the heat continued until the contents of the crucible are white. The loss in weight represents casein, and the residue in the crucible, mineral matter.
Page 15 - PHOSPHORIC ACID. Place 2 grams of the sample on a 9-cm filter, wash with successive small portions of water, allowing each portion to pass through before adding more, until the filtrate measures about 250 cc. If the filtrate be turbid, add a little nitric acid. Make up to any convenient definite volume, mix well, use an aliquot, and proceed as under total phosphoric acid.
Page 197 - ... in a glassstoppered flask. Add to this 5 cc. of strong hydrochloric acid. Allow the solution of sodium thiosulphate to flow slowly into the flask until the yellow color of the liquid has almost disappeared. Add a few drops of the starch paste, and with constant shaking continue to add the sodium thiosulphate solution until the blue color just disappears.
Page 201 - If the mixture froth badly, a small piece of paraffin may be added to prevent it. The heat is then raised until the acid boils briskly. No further attention is required till the contents of the flask have become a clear liquid, which is colorless, or at least has only a very pale straw color.
Page 195 - The flask during the saponification, which should last one hour, should be gently rotated from time to time, being careful not to project the soap for any distance up its sides. At the end of an hour the flask, after having been cooled to near the room temperature, is opened.
Page 219 - The disc having been placed in position, the water in the beaker-glass is slowly heated, and kept constantly stirred by means of the blowing apparatus already described. When the temperature of the alcohol-water mixture rises to about 6 below the melting-point, the disc of fat begins to shrivel, and gradually rolls up into an irregular mass.

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