Extrication of Barium, Strontium and Calciutn. 267 



It is evident that opposite and crossing currents of wind are 

 capable of producing also whirlwinds whose axes should run par- 

 allel with the earth. These must likewise produce great mix- 

 tures of the upper and lower strata of air, and give rise to rain 

 and hail. This seems to correspond very well with our storms ; 

 but I am not yet able to say how far we can carry this opinion.* 



Art. IX. — Brief notice of the Extrication of Barium, Stron- 

 tium and Calcium hy exposure of their chlo7'ides to a powerful 

 voltaic circuit in contact loith mercury as a ^^ cathode f and the 

 distillation of the resulting amalgams by ??ieans of vessels of 

 iron. 



Agreeably to the statements made by Sir Humphrey Davy in 

 his Bakerian lecture, that celebrated chemist was not quite suc- 

 cessful in isolating either barium or strontium, as he declares that 

 he was not enabled to expel from them completely the mercury, 

 by amalgamation with which they had been reduced to the me- 

 tallic state from that of oxide. In the most successful experi- 

 ments made by him, for the isolation of calcium, the tube broke, 

 and the mass took fire before the distillation was accomplished. 



Dr. Hare has recently obtained by an improved process all three 

 of the metals above mentioned. In this, saturated solutions 

 of the chlorides, are substituted for moistened oxides ; the mer- 

 cury and the solutions being both refrigerated by ice- water, or a 

 freezing mixture within receptacles contrived for the purpose. 

 Two deflagrators each comprising one hundred Cruikshank pairs, 

 severally exposing one hundred inches of zinc surface were em- 

 ployed alternately. In consequence of this mode of operating, 

 the charge of acid, at first feeble, was gradually strengthened by 

 additions so as to render the reaction towards the close as forcible 

 as at the commencement. This is highly important, since the 

 difficulty of decomposing the chloride increases with the quantity 

 of calcium combined with the mercury. 



The resulting amalgams were severally subjected to distillation 

 by means of a crucible enclosed in an air-tight iron alembic be- 

 ing protected from the access of air by caoutchouchine naphtha, 

 mercury and desiccated hydrogen. For the complete expulsion 



* From " Schumacher's JahrhuchfUr 1833." 



