G. jS. Jamieson — Determination of Mercury. 351 



the washed and dried residue. The following results were 

 obtained : 



Substance taken 



KI0 3 used 



HgCl found 



•4811S 



16'50 cc 



53-91$ 



'6183 



23-25 



53-89 



•1976 



gravimetric 



53-94 



•5694 



a 



54-00 



The method was applied also to the determination of mer- 

 cury in a mercuric compound by converting the latter into 

 mercurous chloride and then titrating. For this purpose 

 weighed portions of mercuric chloride were dissolved in warm 

 water with the addition of a few drops of hydrochloric acid ; 

 an excess of phosphorous acid solution was then added, and 

 after thorough stirring the precipitate in each case was allowed 

 to settle for about twelve hours. It was then collected on a 

 filter paper and well washed with cold water. The precipitate 

 with the paper was put into the titration bottle, and any pre- 

 cipitate adhering to the beaker and stirring rod was collected 

 by wiping with a piece of filter paper and also put into the 

 bottle. The titrations were carried out as previously described 

 with the following results : (l cc KI0 3 = -013354^Hg) 





HgCl 2 



KIO3 sol. 









No. 



taken 



used 



Hg found 



Hg calc. 



Error 



I 



•3934S 



2r7 cc 



•2898S 



•2904S' 



— -0006S 



II 



•3107 



17-2 



•2297 



•2294 



+ •0003 



III 



•4903 



27-1 



•3619 



•3619 



•0000 



IV 



•3315 



18-3 



•2444 



•2447 



— •0003 



V 



•3407 



18-8 



•2511 



•2515 



— •0004 



The results show that the method is an accurate one. 



Sheffield Scientific School. 



New Haven, Conn., February, 1912. 



