1790-1845. British chemist and meteorologist 
who invented a primary electrical cell in 
1836, the Daniell cell consists of a central 
zinc cathode dipping into a porous pot 
containing zinc sulphate solution. The porous 
pot is, in turn, immersed in a solution of 
copper sulphate contained in a copper can, 
which acts as the cell's anode. The use of a 
porous barrier prevents polarization (the 
covering of the anode with small bubbles of 
hydrogen gas) and allows the cell to generate 
a continuous current of electricity.