120 Ellen Glediisch—* Life of Radium. 



manganese and rare earths, sometimes covers the crystal faces 

 of the broggerite and then cannot be separated completely from 

 it. But while the broggerite dissolves quite easily in nitric 

 acid, the columbite is not attacked and is left in the residue. 



200 grams of mineral were treated with nitric acid (30 per 

 cent). All the broggerite was dissolved and the solution was 

 filtered ; the residue was submitted to a further treatment 

 which will be given below and which proved that no uranium 

 was contained in it. The mineral solution was evaporated to 

 dryness, the residue was moistened with nitric acid, treated 

 with hot water and dissolved. A very slight residue was left 

 undissolved ; it consisted of silica and was added to the first 

 residue. The filtrate was treated with an excess of hydrogen 

 sulphide and the sulphides removed. A current of air was 

 passed through the solution to expel the excess of hydrogen 

 sulphide; the solution was heated to boiling and oxalic acid 

 added. The precipitation was immediate and abundant. The 

 next day the oxalates were filtered off; the solution was heated, 

 2 grams of thorium nitrate were added and precipitated again 

 with an excess of oxalic acid. The oxalates were removed 

 after some hours and added to the first precipitated oxalates. 

 They were gently ignited to form the oxides and* further 

 heated with sulphuric acid. The sulphates formed were dis- 

 solved in water and the hydroxides precipitated five times. 

 The final precipitate was dissolved in dilute hydrochloric acid 

 and brought into a glass bulb where the growth of radium 

 could be tested from time to time : main solution from Brog- . 

 gerite. 



Table 6. 



Growth of radium in the main solution from Broggerite 1. 



Eadium emanation found 



Growth of radium 

 per day 



0-0467 X 10" 9 

 0-0470 X 10- 9 

 0-0470 X 10- 8 

 0-0471 X ]0- 9 

 0047 X 10-9 



Average growth of radium is 0*047 X 10~ 9 gram. 



The radium present in the solution at the start was 

 3-0 X lO- 9 gram. 



The solution from which the oxalates had been removed was v 

 evaporated to dryness and ignited in order to destroy the oxalic 

 acid. The residue was dissolved in nitric acid and a solution 

 containing two grains of oxides of rare earths from gadolinite 





Time from start 



expressed in 



Test 



in days 



terms of radium 



1 



2-82 



0-874 X lO" 9 



2 



212" 



11-730 X lO" 9 



3 



279- 



14-961 X 10" 9 



4 



311- 



16-526 X lO" 9 



5 



318* 



16886 X Hi- 9 



6 



324- 



17-158 X 10~ 8 



