256 W. CG. May—Determination of Lead as Perowrde. 
Sagem crucible and ignited gently, apart from the filter. 
the per cent of lead was calculated. I generally found no 
trouble in completely removing the a 
foil; should any difficulty be experienced, however, the last 
traces may be converted to the peroxide upon the platinum 
itself, by cautious heating ; and without, in the least, injuring 
the foil. 
Below are the results of several analyses. 
Ae 
Wt. of copper taken=2'3723 Wt. grms. of lead taken=1-7804 grms. Total 41527 
“ “ found—=2°379 we “ “ found= L791 “ 
Per cent “ Misano i rf. Percent’ ‘“ =42°84 
Theory =57'13 Theory =42°87 
II. 
Wt. of copper taken=0.3988 grms. Wt. of lead taken="3857 grms. Total 7845 
" “* found=-4001 i See ee 
Per cent “ 5 oe Oe ce Por cont.) eee 
Theor = 50°84 Theory =49°16 
Il. 
Wt. of copper taken="4740 grms, Wt. of lead taken=-0907 grms. Total "5647 
“ * found "4137 « © found="0895 ‘“ 
Per cent “ eo = Saoe Per cent “Sib 84 
Theory = 83°94 Theory = 16.06 
LV. 
Wt. of copper taken=.5461 grms. Wt. of lead taken=0246 grms. Total *5707 
oe See See * “© found=0240 -* 
=95°63 Percent “ “ =4'2 
Per cent “ 4 =4°20 
Theory =95°69 Theory =431 
Vv. 
Wt. of copper taken=2201 grms. Wt. of lead taken=°0260 grms. Total “2461 
: ound ="0248 
found="2205 wo f " 
Percent“ ‘“ =89°59 Per cent“ “ 0 
Theory =89'44 Theory =10°56 
VL. 
Wt. of copper taken='4666 grms, Wt. of lead taken="4109 grms. Total ‘8775 
fo Sou aGeo o “ —™ found=‘4070—“* 
Per cent “ «  =68.50 Percent “ “ =46°38 
Theory =53'17 Theory = 46°82 
These results were obtained by the process previously de- 
ibed and under the conditions there detailed, and seem quite 
satisfactory, especially the first three. The plus error 0 the 
copper was probably due to slight oxidation of the metal 
upon the edges, 
