GALVANISM. 5 



lie between -j^ and ^^, but that even 3^ would 

 save half the copper of the British navy. 



Weak solutions of salt were found to act strongly 

 on copper, but strong ones did not affect it.* 



* Although the experiments of Sir H. Davy have proved the 

 power of iron to prevent the oxidation of copper, it has failed to 

 cure the greater evil, the accumulation of weeds and shells on the 

 bottom, to provide against which copper was first introduced. 

 The government, it is said, have discontinued the practice of 

 applying iron protectors. 



