234 



Intelligence and Miscellaneous Articles. 



IODINE IN CADMIUM. 



Iodine is found in the great zinc foundry at Konigshute in Upper 

 Silesia, in the cadmium which accompanies the zinc ores. — Ibid. 



ANALYSIS OF THE GREEN IRON ORE AND ARSENIATE OF LEAD. 



According to Dr. Karsten, a variety of this ore from the Hollester 

 mines near Siegen, in Rhein Prussia, consists of 



Oxide of iron 63*450 



Phosphoric acid 27*717 



Water 8*560 



99*727 

 And according to the same authority, a variety of arseniate of lead 

 from Herrhausen near Siegen, in Rhein Prussia, consists of 



Oxide of lead 6997 



Muriatic acid 0*81 



Arsenic acid 29*22 



10000 

 The results of this analysis are not accordant with those obtained by 

 Dr. Wohler. — Voggendorff's Annalen, vol. iv. p. 161. 



GEOMETRICAL PROBLEM. BY MR. J. ROBOTHAM. 



Required, a square equal in area to the space comprised between 

 the arcs [AB, DC, and EF, DC,] of two 

 concentric circles, and two parallel right 

 lines, tangents to the interior circle. The 

 area of the exterior circle being double that 

 of the interior. 



Let ABFE, and d C v D be the two con- 

 centric circles. Bisect the quadrant ao f a \ 

 by the line o B. Then by the nature of the 

 problem, the area aB d e = d e o = e o C. 

 To each of these equals add the area e BC, 

 then will the area of the space a BC d = 

 the area of the triangle oBC. And since 

 o a — oB, the square, described on oa, viz. aofb = 4 times the 

 area of the triangle o BC =the space AB, DC, and EF, DC. Which 

 may be seen by drawingthe diagonal af. 



SCIENTIFIC BOOKS. 



Just Published. 

 The 19th Number of Leybourn's Mathematical Repository ; con- 

 taining twenty mathematical questions, and their answers, selected 

 from an extensive correspondence. — Horse Arithmetics, by Mr. 

 Horner. — On Porisms, by Mr. Galloway. — On Central Forces, by 

 the Rev. Mr. Bromhead. — On Equations, by the Rev. Mr. Hawkes. 



—On 



