Contractions. - Ferr-mag. F-mg.

Present name. - Black or Magnetic Oxide, Loadstone. Fe3O4.

It may be prepared as follows: - Take of

Solution of Persulphate of Iron .

5 1/2 fluid ounces;

Sulphate of Iron .

2 ounces;

Solution of Soda

4 pints;

Distilled Water

A sufficiency.

Dissolve the Sulphate of Iron in 2 pints of the water and add to it the Solution of Persulphate of Iron, then mix this with the Solution of Soda, stirring them well together. Boil the mixture, let it stand for two hours, stirring it occasionally, then put it on a calico filter, and when the liquid has drained away wash the precipitate with distilled water until what passes through the filter ceases to give a precipitate with Chloride of Barium. Lastly, dry the precipitate at a temperature not exceeding 120°.

Characters and Tests. - Brownish-black, destitute of taste, strongly attracted by the magnet. It dissolves without effervescence in Hydrochloric Acid diluted with half its volume of water, and the solution thus obtained gives blue precipitates with the red and yellow Prussiates of Potash. When a small quantity is heated in a dry test-tube by the flame of a lamp, a deposit of moisture takes place in the cool part of the tube. 20 grains dissolved in Hydrochloric Acid continue to give a blue precipitate with the red Prussiate of Potash until 83 grain measures of the volumetric solution of Bichromate of Potash have been added.

Preparation. - Trituration.

Reference to Horn. Proving. - Caspari, Allg. Horn. Diagnostik.

Proper forms for dispensing. - lx to 3, Trituration only. 4, dilute Tincture only. 5 and upwards, Tincture, Pilules, or Globules.