116 



DR. J. P. JOULE ON SOME AMALGAMS. 



grees lost its fluidity, until at length a mass of crystals 

 of amalgam was formed having a greyish- white colour of 

 metallic brilliancy. The time required to complete the 

 operation was generally about one day ; but a longer or 

 shorter period was occupied in some instances, in conse- 

 quence of variations in the quantity of mercury employed, 

 and in the efficiency of the voltaic arrangement. The fol- 

 lowing Table contains the results of most of the experiments 

 made on the amalgam of iron. The analysis of this and 

 other amalgams was made by heating them in a glass 

 tube through which a current of hydrogen was passed. 



No. 



Composition. 



Sp. grav. 



Remarks. 



Mercury. 



Iron. 



I. 



2. 



3- 

 4- 

 5- 

 6. 



7- 

 8. 



9- 



lO. 



lOO 



5> 

 J> 

 )> 

 5J 



>> 



5> 

 5> 



5> 

 5) 



0-I43 



i'39 



2-97 



11-8 



i8-3 



47'5 

 127-6 



k 14-74 



79 

 103-2 





Perfectly fluid. 



Fluid. 



Semifluid. 



Soft. 



Solid : colour, greyish white. 



Solid : good metallic lustre. 



Solid: friable. 



The superfluous mercury pressed out 



from the semifluid amalgam by 



hand. 

 Compressed rapidly, and with a force 



of fifty tons on the square inch. 

 Ditto. 





12-19 





1011 









No. 5 of the above Table was a solid amalgam of a 

 greyish white, approaching the colour of iron. It could 

 be easily broken into powder. When dried and left un- 

 disturbed, it soon became covered with small globules 

 of mercury, until ultimately it was entirely decomposed. 



To obtain No. 6, 1 used a solution of chloride of iron 

 instead of the sulphate which was used in all the other 

 experiments. 



No. 7 could be easily reduced to powder. It had a 

 bluish colour, and was destitute of metallic lustre until 

 it was rubbed. It remained some time under water with- 

 out change, but when dried became speedily decomposed, 



