Mr. Warington on the Molecular Structure of Silver; SOS 



which gives 4 atoms in the magnesia, zinc and iron salts, and 

 2 in those of manganese and copper, the per-centage of water 

 observed being in all cases rather above the atomic quantity, 

 from water mechanically included; double salts being, as is 

 well known, remarkable for the quantity of hygrometric water 

 they retain. 



The salt of magnesia is generally said, on the authority of 

 Dr. Murray, to contain 6 atoms of water, but I have never 

 found it to contain more than 4. 



These salts are persistent in air, and may be dried at 212° 

 without losing their transparency; the salts of manganese and 

 magnesia decrepitate strongly when heated. 



After the loss of their water, these salts are all fusible at a 

 low red heat, and undergo that change without decomposition. 

 When the double salt is dissolved in water and the solu- 

 tion allowed to evaporate spontaneously, its component salts 

 always crystallize apart, the double salt being entirely de- 

 composed ; this often happens also with bisulphate of soda. 

 In consequence of this effect of water the solubility at a low 

 temperature could not be observed. 



When a solution of the copper salt is boiled, a subsalt is 

 precipitated, resembling the subsalt of copper and potash 

 formed under similar circumstances. It is of a pale green 

 colour, loses nothing by drying at 212°, but loses weight and 

 becomes much deeper in colour when ignited; it therefore 

 contains water besides an excess of oxide of copper. 



LXXIII. On a curious Change in the Molecular Structure of 



Silver. By Robert Warington, Esq.* 

 r T' , HE subject of the present brief communication was put into 



'• my hands by my friend Mr. Porrett after our last Meet- 

 ing, as bearing on the subject of the memoir which I bad the 

 honour of reading before the Society in January 1842f ; a sub- 

 ject I am still prosecuting, as my time will permit, and the re- 

 sults of which I hope to lay before the Society at an early date. 

 It appears, from information furnished me by Mr. Porrett, 

 to have been part of a silver funeral vase, and was discovered 

 by some labourers, about four months since, at the depth of 

 seven feet below the surface of the ground, while digging for 

 brick-earth between Bow and Stratford. Its height was about 

 ten inches, and its greatest diameter about eight inches ; it 

 weighed 40 ounces, and had a smaller vase about the size of 

 a human heart in its interior. When brought to Mr. Ed- 



* Communicated by the Chemical Society; having been read December 

 18, 1843. 



f See Memoirs, vol. i. p. 77. [or Phil. Mag. S. 3. vol. xx. p. 537.] 



