Consultant MHU

Alexander the Great - one of the most famous military strategists ever tried to
invade India and found himself unable to pry open the defences of the Indian
king Porus for a few days. The best of his artillery and catapults did not dent
the Indian fortresses. Frustrated, he sought the expert advice of a consultant
on what artillery to use to get the most effective and impressive results.
After much analysis, the consultant came up with this very powerful device
which Alexander used to immediate effect - the fortress was breached within no
time at all... The question is....







What device did the consultant suggest?















Ans: 'Jar-guns' :)