512 



Dr. E. J. Mills on Elective Attraction. 



nitrate, nor confined to its due distilling-point (below 110°), 

 would be likely to afi'ect a converse transformation. 





I. 



II. 



III. 



IV. 



V. 



Plumbic nitrate employed... 

 Residue oi)tained 



[2-7727 

 2-7945 

 125° 



viz. : — 



10-76 

 202 



86-41 



39858 

 40138 

 137'^ 



10-09 

 167 



87-29 



2-7045 

 2-7472 

 131°-5 



12 65 

 2-63 



83 38 



3-4883 



35477 



130° 



8-11 



1-98 



88-67 



3-1795 



3-2260 



130° 



1107 



2-20 



8537 



Temperature 



Composition of the residue, 

 Plumbic chloride 



Phosphoric oxide 



Plumbic nitrate 





9919 



9905 



98-66 



98-76 



98-64 



The values of « are 



5-44 



6-17 



4-91 



4-18 



5-14 





The mean is 5*17; probable error 0*19. 

 Were the equation 



3Pb(N03)2 + 2POC13=Pb3(PO^)2 + 6N02Cl 



true, under the experimental conditions, the residue would con- 

 tain no chlorine, it would be neutral to wet litmus, and, in any 

 case, would weigh less than the original nitrate (for a total 

 attack, 08534 of the nitrate). The above results, however, 

 agree with neither of these suppositions. 



Thallous Nitrate. 



The thallous nitrate employed was free from sulphate and 

 thallic salt; 1*2045 grm. of it yielded 1*1358 grm. sulphate 

 = 94*30 per cent, (theoretically 94*72 per cent.). For experi- 

 ment it was dried for several hours at 156° and cooled in the 

 desiccator. 



Phosphoric oxychloride hardly acted on thallous nitrate in the 

 cold ; but at 45° a yellow coloration was observed, which became 

 red at 71°-75°, with turbidity. At 75°-80° the maximum 

 change occurred, and a gas, having the unmistakable colour of 

 nitric peroxide, was given off freely. Soon afterwards the reac- 

 tion ceased. It was noticed, however, that on raising the tem- 

 perature to 116°-118°*5, a very small quantity of a greenish gas 

 was evolved, apparently chlorine. Each operation occupied 

 rather more than an hour. The residue had a very pale yellow 

 tint with a white border, and on the addition of water disengaged 

 heat. Its aqueous solution gave a brown precipitate with am- 

 monia. The course of analysis differed in no respect from that 

 pursued in the case of the lead salt. 



