Glass rod, being an insulator can be charged by holding it in our hand. This is because, the transfer of charge from the surface of the glass to our body does not take place. Hence, the glass remains charged.

Iron rod cannot be charged by rubbing when held in hand. Iron being a good conductor of electricity, transfer the charge produced on it into our body and is further transferred into the earth through our body. Therefore, the iron rod will continuously remain charge free. 

The given figure shows the lightning conductor. 

Ligtning conductor is used to protect buildings and houses from lightning. A metallic rod, taller than building is installed in the walls of the building during it's construction. The upper part of the ligtning conductor is left in the open and other end is buried deep into the ground. 

When lightning strikes, the rod provides easy route for the transfer of electric charge to the ground. 

The process in which negative and positive charges meet to produce streaks of bright light and sound is called electric discharge.