MINERALOGY. 461 



proved methods in deteriniuiiig the boron. Pentield and Sperry^ have 

 also worked in the same line, and their analyses of howlite prove that it 

 is in fact a silicoborate, not a mixtnre as had been suggested before, and 

 having the comi)osition flr.Ca^B-.SiOi,. 



Jaunasch^ has analyzed a series of heulandites from diiierent locali- 

 ties and proved that they contain considerable amounts of strontium (up 

 to 3.6 per cent.) which must have been overlooked by earlier analysts. 

 Linck^ has made an examination of some iron sulphates from Chili on 

 both the chemical and crystallographic side, adding a new species 

 (queustedtite, see beyond) and also new points about copiapite, coquim- 

 bite and roemerite, halotrichite and fibroferrite. The work of Frenzel 

 and Darapsky in the same direction is mentioned on a later page. 



Eakins* gives descriptions and analyses of two sulphantimonites from 

 Colorado, one of which is a fieieslebenite containing only lead ; the 

 other has the composition 3PbS.2Sb2S:i. An inaugural dissertation by 

 Carl Hersch is devoted to the discussion of the water in the zeolites 

 with numerous analyses. Another by Vogel gives a number of analy- 

 ses of vesuviahite from different localities, without, however, attempt- 

 ing to establish a new formula. Still another by jSToelting discusses 

 the relations of the "Schalenblende" to the ordinary isometric sphale- 

 rite and the hexagonal wurtzite. He finds that wurtzite is generally 

 present, and probably in many cases has been formed by molecular re- 

 arrangement from the original sphalerite. 



An important series of papers by Julien^ discusses at length the re- 

 lations of the different minerals coming under the general head of iron 

 pyrites, pyrite, marcasite, and pyrrhotite, especially as regards their oc- 

 currence together. The varying physical characters of pyrite, specific 

 gravity, color, and especially resistance to change, are found to be due 

 to the presence of marcasite — the less stable compound — with it in dif- 

 ferent proportions. This is shown to have important applications as 

 affecting the durability of building stones containing iron pj^rites. The 

 alteration of pyroxene into serpentine has been minutely studied by 

 Merrill" for the locality at Montville, New Jersey. The jade articles in 

 the Washington Museum have been studied chemically and microscop- 

 ically by Clarke and Merrill.^ 



The synthetic formation of minerals has been further studied by 

 some of the French chemists, who have already done such important 

 work in this direction. Among the various contributions in this field 

 are the formation of crocoite, celestite, anglesite, hydrocerussite, by 

 Bourgeois; of pharmacolite, by Duf^t ; of zincite, frauklinite, magne- 

 tite, tephroite, rhodonite, wollastonite, barite, celestite, anhydrite, 

 pyrolusite, by Gorgeu ; quartz and tridymite, by Kroustchoff; of pyro- 



' Ihid., p. 220. 1 5^nn. New York Acad. Sci. 



-Ber. Chem. Ges., Berlin, vol. xx, :J4i). ''Proc. U. S. Nat. Museum, p. 105, 1886'. 



3Zeitschr. Kryst., vol. xv, 1. ^ Ibid., p. 115. 



■• Amer. Jour. Sci., 1880, vol. xxxvi, 450. , 



