is a mineral found in Extremadura. It is of a whitish colour, and of great solidity, though not sufficiently hard to strike fire with steel. If triturated in an iron mortar in the dark, or even if two pieces of it be rubbed together, it becomes luminous; but when it has once lost this property, it does not, like some natural phosphori, receive it again by being exposed to the rays of the sun. If reduced to a very fine powder, and laid on coals, it does not decrepitate, but burns with a beautiful green light; though, if the coals be very hot, and the powder coarse, decrepitation will take place.
According to the analysis made by these chemists, 100 grains of the calcareous phosphat is resolvable into the following elements:
| Element | Quantity | |--------------------------|----------| | Carbonic acid | 1 grain | | Muriatic acid | 1 | | Iron | 1 | | Quartzous earth | 2 | | Pure calcareous earth | 59 | | Phosphoric acid | 34 | | Fluoric acid | 2½ |
100 grains.
We have the following account of an analysis of a native phosphat of lime (earth of bones) by Mr Halphenratz in the Annals of Chemistry. "The phosphat of lime of Extremadura, found by Mr Proutt, determined me to examine on the coals a phosphorescent powder which I collected at Kobala-Polyana near Sigeth," Sigeth, in the county of Marmarosch, during the metallurgic tour I made through Hungary by command of government. Though this powder gives absolutely the same appearance when treated on the coals as the flint of lime (phosphorus), yet no fluorine acid is disengaged from it when heated with sulphuric acid. It dissolves in nitric acid (dephlogisticated nitrous acid); and sulphuric (vitriolic) acid precipitates from this solution a considerable quantity of sulfate of lime (gypsum): the liquor filtered, and concentrated by evaporation, gives a new precipitate similar to the former. The liquor again filtered, and evaporated to dryness, left a slight residuum. This residuum, after having been exposed to a fire sufficiently strong to make the vessel containing it red-hot, and disengage the nitric and sulphuric acids which might have remained united with it, was soluble in distilled water, which it acidified. This acid did not precipitate barbic acid; it caused a white precipitate from the solutions of sulfate of iron (green vitriol), and nitrate of mercury (mercurial nitre), and formed a thick and copious one in lime water: hence it is evident, that this acid was the phosphoric, and the powder was phosphate of lime.
The phosphate of soda is obtained by combining the phosphoric acid with the mineral alkali. It has, we are told, been given with success as a purge; and M. Pelletier thinks it may be applied to the soldering of metals instead of borax: and indeed it resembles this substance so much in many of its properties, that it has been supposed that phosphoric acid is one of the constituent principles of borax. See Chemistry, p. 924.