Mineralogy and Geology. 421 
treme slowness through the filter from the free state of the precipitated 
oxyd of irons The magnesia was separated by two methods, either b 
dissolving the earth in hydrochloric acid, adding sal ammoniac and 
neutralizing with ammonia, or, by digesting the earth in water acidu- 
laied with a few drops of nitric acid. In consequence, however, of 
the new earth being slightly soluble in sal-ammoniac and in dilute nitric 
acid some loss is sustained by this method, and therefore it is not appli- 
cable to quantitative analysis 
When thus se apart ated ihis earth has the following sepphisies and re- 
action with reagen 
t dissolves readily either in ae: apse or pe acid, evolving 
chlorine from the former acid. The solut n hydrochloric acid, 
when concentrated, has a beautiful. pea sites ste and the salt erys- 
tallizes either of a slightly paler green or a light chrome yellow, de- 
pending on the degree of heat at which the evaporation is completed. 
The peculiar color of ils salts together with the appearance of the 
residue left in the analytical process s afier treating with caustic potash to 
separate the alumina was what first attracted my attention to this earth. 
The solution of, the earth in itp dials acid gives the fol- 
lowing reactions with reagen 
mmonia, a white, bulky oe. Lg sparingly: soluble in éal- 
ammoniac. This is one of ihe characters which distinguish it from 
magnesia. Oxalate of ammonia, a aie precipiiate in neutral solu- 
tious ; another Gaiman between it and magnesia. Oxalic acid, no 
precipitate until quite neutralized by ammonia. Bi-carbonate of potash, 
white eepeireeing anesrney slightly soluble in excess. Phosphate of 
da the 
the reagent be added without disturbing the fluid, a number of little 
vesicles are formed, which remain distinct, as if each were enclosed in 
a delicate ieanslueett membra errocyanid of potash, a white 
prea with a slight tinge of, bluish green, whieh seemed to be 
independent df any remaining trace of oxyd o of iron; prypaiie in aan 
due to ie ie of the reagent itself. Hydrosulphuret of am onia, a 
white precipitate. Succinate of ammonia, a white pane naidg even in 
slightly acid solutions. Benzoate of ammonia, the same, with a tinge 
of yellow. Crystals of sulphate of potash inserted in the solution gave 
buta very slight precipitate, and that only after long standing, ‘The 
precipitate of phosphate of soda is soluble only in a considerable por- 
- of muriatic acid, and is not precipitated by boiling 
When separated, and still slightly contaminated i! magnesia, the 
earth has a pale flesh color, not unlike yttria. When freed - the 
character of the precipitate with phosphate ¢ of soda; in being  precipi- 
tated by oxalate of ammouia, From yitria it differs in not giving a 
precipitate with oxalic acid in slightly acid solutions ; in ie precipi- 
tated by succinate of ammonia, even before the solution is quite neu- 
tral, which prevents this reagent being applied to separate iron from it, 
