150 S. Poioers — Granite in Kansas. 



making an angle of 125° with the main Appalachian trend, 

 there is a rather striking arrangement of the Cincinnati, Nash- 

 ville, and Ozark areas, and the Kansas granite, in an inner arc 

 with a general axis from 100 to 300 miles west and north 

 of the inner bonndarj^ of the main Appalachian axis. 



The Kansas granite may therefore represent either au out- 

 lier of pre-Cambrian structure connected with the Lake 

 Superior region, or a Lower Paleozoic uplift from the top of 

 which the sediments were removed in pre-Pennsjlvanian time, 

 leaving only peaks of pre-Cambrian granite to be buried by 

 Pennsylvanian sediments just as the peaks of the Wichita 

 Mountains at the present time represent a formerly extensive 

 mountain range now almost completely buried by horizontally 

 bedded sediments. 



Art. Xy. — A New Method for the Determination of 

 Hydrogen Peroxide ; by George S. Jamieson. 



The method to be described is based upon adding a meas- 

 ured volume of hydrogen peroxide solution to an alkaline 

 solution containing an excess of standard sodium arsenite. 

 When the reaction is completed concentrated hydrochloric 

 acid is added and the unaltered arsenite is titrated with a 

 standard solution of potassium iodate"^ using a chloroform 

 indicator. The amount of arsenite found by titration is 

 deducted from the amount taken, giving that oxidized by the 

 hydrogen peroxide. In order to obtain a quantitative reaction 

 with the hydrogen peroxide and the sodium arsenite it was 

 found necessary to add sodium hydroxide in excess as directed, 

 below. It should be observed that this method is not influ- 

 enced by the presence of organic preservatives as is the case 

 with the well known permanganate method. f Also it has the 

 advantage over the excellent Kingzett methodj in that both 

 the sodium arsenite and the potassium iodate solutions are 

 remarkably stable. These solutions can be made of known 

 strength without standardization and used immediately which 

 is in marked contrast with the sodium thiosulphate solution 

 employed in the Kingzett method. Furthermore, it has been 

 found that the iodate method gives accurate results. 



* J. Incl. and Eng. Chem., iii, 250, 1911. 



\ Analyst, viii, 36. 



tJ. Chem. Soc, 1880, 792. 



