168 Intelligence and Miscellaneous Articles. 



that I then said, " If no one better can be found, I perhaps might 

 take it, were it offered me, but I will not ask for it." 



Sir Humphry Davy then said to me, " If you will now take the 

 Secretaryship, no one else shall have it ; to which I replied, " My 

 dear Sir Humphry, the thing is impossible. In the letter that you 

 have in your hand I have solicited you to give the appointment to 

 Mr. Babbage, and I would cut my right hand off sooner than you 



and Wollaston should say of me, as both of you said of , 



that ' he went to to get the Clerkship of the Irons for 



Children, but that he came back, having secured it for himself ! ' ' 



Sir Humphry then said, " I have not given the place to Children, 

 nor have I actually promised it to him, but I will not give it to 

 Babbage. " 



Under the foregoing facts and circumstances, it would be an unjus- 

 tifiable encroachment upon your time, if I were at greater length to 

 trespass upon your attention, except it be to remark — 

 "Facilis descensus Averni; 

 Sed revocare gradum, superasque evadere ad auras, 

 Hie labor, hoc opus est." 



I am, dear Dr. John Davy, 



Yours very faithfully, 



J. South. 

 P.S. — You have my permission to publish this letter. — J. S. 



SIMPLE METHOD OF PREPARING THALLIUM. BY R. BUNSEN. 



In a large sulphate- of- zinc works at Goslar, a lye is evaporated, 

 obtained from the Rammelsberg pyrites which is so rich in thallium 

 that pounds of this metal can be readily obtained from it. It con- 

 tains, besides other constituents, 21" 74 per cent, of sulphate of zinc, 

 0*536 of sulphate of cadmium, O05 of chloride of thallium, and 0'28 

 of sulphate of copper. Mixed with an equal volume of hydrochloric 

 acid, an immediate precipitate of chloride of thallium is obtained. 

 When iodide of potassium is added to it in the presence of an ade- 

 quate quantity of hyposulphite of soda, iodide of thallium is preci- 

 pitated, mixed, however, with some subiodide of copper if the quan- 

 tity of hyposulphite is insufficient. But as the addition of these sub- 

 stances hinders the production of white vitriol, I have found a way 

 which is not only simpler, but which also introduces an essential 

 improvement in the manufacture. It consists in placing in the cold 

 lye sheets of zinc, by which copper, cadmium, and thallium are pre- 

 cipitated. In this way, from a cubic metre of the lye, for 7*4 kilogs. 

 of zinc, 6*4 kilogs. of a spongy metallic precipitate were obtained, 

 which was rapidly washed out in a flannel bag. Besides some lead 

 and zinc, this contained 4*2 kilogs. of cadmium, 1*6 kilog. of cop- 

 per, and 0*6 kilog. of thallium. When digested with water to which 

 some sulphuric acid was added from time to time, the cadmium and 

 thallium dissolved with disengagement of hydrogen, leaving the 

 copper. To the sulphuric acid solution, 0*5 kilog. of iodide of 

 potassium were added, which precipitated 0*97 kilog. of chemically 

 pure iodide of thallium, which was readily washed by decantation. 

 — Liebig's Annalen, January 1865. 



