24 schaller: ferritungstite 



more or less crystalline state. The bottles containing the solution 

 and precipitates were allowed to stand as long as desired, with 

 occasional shaking, in the laboratory at about 20°. There is no 

 doubt that some of the precipitates were basic but this would 

 make no difference as far as the application to geochemistry is 

 concerned, for, many such salts are well known as minerals. 



In the results below the concentrations are expressed in milli- 

 equivalents per liter, an equivalent being equal in grams to the 

 molecular weight of the metal or radicle reduced to a univalent 

 basis. Where a liter of solution was not employed the results 

 have been calculated to that dilution. The amount of sodium 

 carbonate used was sufficient to precipitate all of one metal only. 

 The results are given in Table I. 



When the results in Table I are considered it is seen that in 

 general the separation is not complete. The metals may be 

 arranged in a series, however, such that the first one is precipi- 

 tated to a greater extent than the next and so on. The complete- 

 ness of the fractionation is greater as the metals are more widely 

 separated in the series, as is shown in Table II. In some cases 

 special reactions occur as, for example, the reduction of silver 

 salts by ferrous and manganous salts, and these experiments are 

 omitted. 



Altho it is incorrect to state that the series represents the order 

 of solubility of the carbonates it does represent the order of the 

 precipitating power of carbonates upon metallic salts under simi- 

 lar conditions. The order is Hg, Pb, Cu, Cd, Zn, Fe, Ni, Mn, 

 Ag, Ca, Mg. The most striking fact, perhaps, is the position of 

 silver which is found between manganese and calcium. 



The effect of bicarbonates and of higher temperatures is under 

 investigation. 



MINERALOGY. — Ferritungstite, a new mineral. WaldemarT. 

 Schaller. Geological Survey. To appear in the American 

 Journal of Science. 



The new mineral ferritungstite is a hydrous ferric tungstate 

 formed by the oxidation of wolframite, with which it occurs in 

 pure and crystalline form as minute hexagonal scales, in the Ger- 



