Intelligence and Miscellaneous Articles. 565 



*t> 



Washingtonite of Shepard, analysed by Mr. J. S. Kendall under 

 the direction of Dr. Jackson, gave these results : — 



Oxygen. Ratio. 



Titanic acid 25-28 4-82 1 



Peroxide of iron 51*84 1036 2 



Protoxide of iron .. 22-86 5'08 1 



99-98 

 The atomic proportions are thus nearly one atom titanic acid, two 

 atoms peroxide of iron, one atom protoxide of iron ; or, a trititaniate 

 of iron, consisting of two atoms trititaniated peroxide and one atom 

 trititaniated protoxide. If we unite the magnesia and lime with 

 protoxide of iron in the following analysis of an ilmenite from Aren- 

 dal*, by Mosander, we obtain precisely the same result. The cry- 

 stalline form of the two varieties is also the same, and there can be no 

 doubt of their identity as one species f. 



Titanic acid 24-19 



Peroxide of iron 53-01 



Protoxide of iron .... 19'91 1 nrj.qo 

 Magnesia and lime . . T01 J 

 By referring to the analyses of ilmenite from other localities, it will 

 be seen that the essential constituents, titanic acid and the two 

 oxides of iron, so interchange with each as to produce different varie- 

 ties, but all having the same crystalline form. 



NOTICE ON CERTAIN IMPURITIES IN COMMERCIAL SULPHATE 

 OF COPPER. BY MR. S. PIESSE. 



One source of the sulphate of copper of commerce is the treat- 

 ment of brass and German silver articles technically called dipping, 

 which consists in plunging them for a short time into a mixture of 

 nitric and sulphuric acids, an operation which removes the coat of 

 oxide from the surface of the metal, and leaves the latter in a clean 

 state proper for the reception of varnislTor other finishing. In time 

 this dipping liquid becomes in great measure saturated, and after 

 neutralization with old copper yields on evaporation in leaden pans 

 a large quantity of sulphate of copper in crystals. According to 

 the author not less than 100 tons of dipping liquid are thus disposed 

 of annually at Birmingham by the makers of buttons and other arti- 



* The hystatite of Breithaupt. 



f An acute rhomboheclron, P on P 86° 10', for the ilmenite. Shepard, 

 employing varnished planes of the washingtonite, makes P on P 86°. Prof. 

 Shepard founds the distinction on other than crystallographical characters; 

 for, he says, it is not thus " shown to be distinct, in any essential manner, 

 from the axotomous iron ore of Mohs, or from crichtonite (including ilme- 

 nite) : indeed, it appears most probable that all these minerals are not only 

 identical in their angles, but are isomorphous with specular iron." — Amer. 

 Journ. vol. xliii. p. 365. The analysis, now, would seem to destroy the 

 groundwork for any distinction. 



