294 Extrication of the Alkalijiahle Metals, 



that the deflagrator eminently associated the requisites of which 

 he was in search, and stated many facts and arguments tending 

 to prove that it was the most perfect form of the apparatus at that 

 time known. More than twelve years ago, while I was operating 

 with a deflagrator of three hundred pairs, each seven inches by 

 three, I observed that, in a circuit made through a saturated solu- 

 tion of chloride of calcium, by means of a coarse platina wire 

 (No. 14,) and a fine wire, (No. 26,) that when the latter was made 

 the cathode and the former the anode, a most intense ignition 

 resulted, causing the rapid fusion of the fine wire into globules 

 like common shot. But when the situations of the wires were 

 reversed, so that the smaller wire was made to form the anode, 

 the ignition became comparatively so feeble as to be incompetent 

 to fuse the fine platina wire. This phenomenon had continued 

 to appear inexplicable, when, during the last winter, it occurred 

 to me that the evolution and combustion of the calcium might be 

 the cause of the superior heat produced at the cathode. 



This led to the employment of chlorides in the process of 

 Seebeck, Berzelius, and Pontin, for the production of amalgams 

 from the earths, in which a cathode of mercury, and anode of pla- 

 tina were used. Accordingly, in operating with a deflagrator of 

 three hundred and fifty Cruickshank pairs of seven inches by three, 

 a mercurial amalgam was speedily obtained, which appeared suf- 

 ficiently imbued with calcium to become speedily buried under 

 a pulverulent stratum of lime, and mercury in a minute state of 

 division. 



Nevertheless, after exposure of the amalgam thus produced to 

 the air, till all the calcium had been separated, and igniting the 

 resulting powder to drive off" the adhering mercury, the ratio of the 

 weight of the hme thus obtained, to the mercury with which it 

 had been united, was not over a five hundredth part. With a 

 view to procure an amalgam in which the proportion of calcium 

 should be greater, I was led to devise the following apparatus and 

 process, of which an engraving and description are now laid be- 

 fore the society. 



How far the result of my exertions, subsequently stated, may 

 be considered in advance of the steps previously taken, will be 

 evident from the fact that all the knowledge which exists, res- 

 pecting the isolation of the metals of the alkaline earths, is due 

 to the experiments and observations of Davy ; and to what point 



