274 Chronicles of Science. [April, 



Kenngott's observations are of considerable interest, from their 

 bearing on the constitution of other zeolitic minerals. 



Among the researches conducted in the laboratory of Zurich, 

 the results of which have lately been published in the ' Journal 

 fur praktische Cheinie,' we notice several mineralogical investiga- 

 tions. Herr Stadeler has chemically examined the topaz, and the 

 silicate of iron called lievrite ; while Dr. Wartha has investigated 

 the minerals pennine and wiserine. The last of these papers is of 

 interest as showing the folly of rashly instituting new species. 

 Wiserine is a Swiss mineral occurring in pale clove-brown tetrago- 

 nal crystals, resembling those of zircon. Its chemical composition 

 was not well known, but it was supposed to contain silica and 

 titanic acid. This is, however, entirely disproved by Dr. Wartha"s 

 analysis, which shows it to be a phosphate of yttria, agreeing with 

 the Norwegian species known as XenoUme. Its occurrence is 

 notable as being the first yttria-bearing mineral found in Switzer- 

 land. 



Several other papers in the same journal merit the attention of 

 the mineralogist. The green colour presented by many sandstones, 

 marls, and other sedimentary rocks, is usually referred to the 

 presence of disseminated granules of glauconite — a mineral which, 

 although by no means confined to any particular geological age, is 

 especially abundant in certain Cretaceous deposits, such as the 

 typical " greensand " of our own country. So difficult is it to dis- 

 sociate these mineral-grains from the rock in which they are 

 embedded, and so readily do they suffer alteration by the action of 

 decomposing influences, that the analyses which have from time to 

 time been published present discrepancies of such magnitude, as 

 to induce Dr. Haushoi'er to thoroughly examine the mineral with a 

 view to determine its true chemical composition. In his paper " On 

 the Composition of Glauconite," * he publishes no less than seven- 

 teen original analyses of this mineral from different Bavarian rocks, 

 obtained through Professor Gunibel. From these researches he 

 concludes that all the varieties of glauconite are referable to a single 

 species, but that their composition is not reducible to one general 

 expression. The author calls attention to the relation between the 

 constitution of the mineral in question and that of certain varieties 

 of seladonite, or green-earth ; at the same time expressing a belief 

 that many so-called chloritic rocks are in reality glauconitic. In all 

 cases the mineral appears to be a secondary product, derived from 

 the surrounding rocks. According to Ehrenberg the grains often 

 consist of the casts of microscopic foraminifera, and hence it is 

 usually assumed that organic substances have been concerned in the 

 formation of the mineral ; an assumption which Haushofer is led to 

 doubt, from the striking paucity of organic remains in glanconitic 



* ' Journ. fiir praktische Chemie,' 1866, No. 6, p. 353. 



