Intelligence and Miscellaneous Articles. 539 



of water, the latter only half an atom, and treated with potash it yields 

 an oily carburetted hydrogen, while the sulphate of methylene yields 

 none. It is supposed, however, that the compound obtained by S6- 

 rullas is, in fact, a sulphate of methylene, mixed with variable quan- 

 tities of oily cnrburetted hydrogen. 



Sulphate of methylene possesses very important properties, since 

 by its use all the analogous compounds of methylene may be pro- 

 cured. 



When heated with fused common salt, sulphate of soda and gaseous 

 hydrochlorate of methylene are produced. 



Heated with fluoride of potassium, gaseous hydrofluate of methy- 

 lene is obtained, hereafter to be described. 



When it is heated with cyanuret of mercury or cyanuret of potas- 

 sium, sulphate of mercury or of potassium is procured, and at the 

 same time, hydrocyanate of methylene is obtained in a liquid form. 

 When distilled with benzoateof potash, benzoate of methylene is pro- 

 cured, and with dry formiate of soda, formiate of methylene results. 

 When put in contact with saturated alkaline sulphurets, a liquid is 

 obtained analogous to the mercaptan of M. Zeise. 

 [To be continued.] 



PREPARATION OF PURE TELLURIUM. BERZEL1US. 



Telluret of silver having lately been found in Siberia, and telluret 

 of bismuth at Schemnitz, Berzelius has obtained the metal in a pure 

 state from the former by the following process : Mix dry carbonate 

 of potash intimately with the well-pulverized mineral, make it into a 

 thick paste with olive oil, and put it into a porcelain crucible with a 

 cover. The crucible is then to be at first gently heated, till the oil 

 is carbonized ; and when gas ceases to burn at the edges of the cru- 

 cible, the heat is to be raised for a moment to whiteness, and the 

 crucible then allowed to cool. A deep brown porous mass is ob- 

 tained ; it is to be quickly powdered in a dry mortar, and thrown upon 

 a dry filter and washed with boiling distilled water, with as little con- 

 tact of air as possible. 



A liquor of a rich red colour is obtained, which whenever it comes 

 into contact with the air, becomes of the lustre of silver from the 

 tellurium which separates, while the potassium oxidizes by the oxygen 

 of the air. As soon as the liquor passes colourless, the mass on the 

 filter is sufficiently washed, and is composed of charcoal and metallic 

 bismuth, containing mere traces of tellurium. 



The deep red solution contains telluret of potassium mixed with 

 more or less sulphuret and seleniuret of potassium, with a small quan- 

 tity of telluret of gold, copper, manganese, and iron. If the solution 

 be suffered to remain at rest, the surface becomes covered with a 

 pellicle of tellurium, and gradually, but very slowly, it becomes turbid 

 to the bottom : by blowing air into it the mass oxidizes readily. The 

 potassium becomes potash, and the tellurium is precipitated in the 

 metallic state; it may be said that the tellurium is precipitated by 

 oxygen. When the precipitation has ceased, the solution assumes a 

 green colour, and if it be poured off at this moment, it deposits in a few 

 seconds a very small quantity of tellurium, and the liquor becomes 



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