202 EXPERIMENT STATION RECORD. 



the lieiglit of the eolamn through Avhich the tlame is visible, and 

 applying' the lollowing formulas: 



0.590 

 Peicentasi' of H:S04 = 



Peiceutajie of SO3 = 



height of column. 

 0.482 



height of column. 



— B. W. KILGORE. 



Photometric method for the estimation of lime, J. I. D 



Hinds {Chem. Xeics, 73 {1S90), No. 1909, j). 299).—T\i\^ method is sim- 

 ilar to the one for sulphuric acid mentioned above. Solid ammonium 

 oxalate is used as the precipitating reagent and only dilute solutions 

 can be worked, 0.01 to 0.02 per cent giviug best results. The method 

 is not adapted to flaky precipitates or ones large enough to settle 

 rapidly. The equations are: 



0.0642 

 Perceutage of CaCos = 



Percentage of CaO 



height of column — 0,3 



0.0360 

 height of column — 0.3 



For the success of the methods for lime and sulphuric acid the flame 

 must be constant. They are considered especially applicable to the 

 determination of these substances in waters and urine. The author 

 states that the method for calcium carbonate is more accurate than the 

 soap method and is but little aflected by magnesium salts. — B. w. 



KILGORE. 



Detection of small quantities of lead in drinking water, M. 



Antony and T. Benelli {Gazz. chim. Hal., 26 {1890), No. 1, }). 218; abs. 

 in Cliem. Ztg., 20 {1896), No. 54, Bejfert, p. 181). — To avoid evaporating 

 large quantities of the water, it is recommended to dissolve mercuric 

 chlorid in about 4 liters of the water at the rate of about h gm. per liter, 

 and then conduct hydrogen sulphid through the cold liquid. Quan- 

 tities of lead so small as not to be shown by hydrogen sulphid alone 

 are thrown down with the mercury. If the solution after settling is 

 brown colored, it is shaken with ammonium chlorid (about 5 gm. per 

 liter) and allowed to settle, when it should be colorless. The precipi- 

 tate is collected on a filter, washed, dried, and incinerated to drive off 

 the mercury. The residue contains the lead, which is treated with sul- 

 phuric acid and weighed as sulphate. 



A new condenser, R. Walther {Chem. Ztg., 20 (1896), No. 47, p 

 462, Jigs. 3). — This consists of 2 tubes of metal or glass, one within the 

 other, the ends of the outer tube being welded to the inner tube, which 

 is open at both ends, or may be nearly closed at the upper end. The 

 usual inlet and outlet tubes are i)rovi<led at the upper end of the outer 

 tube, and 2 strij)s of metal running lengthwise between the inner and 



