Tension multiplier jar apparatus and method of operation

A tension multiplier jar apparatus which multiplies the tension by a multiple factor using a compressible energizing fluid acting on differential areas to provide greater over-pull to jar objects in the well. There is first included an overall assembly which includes a lowermost anvil and metering sub attached on its upper end to a hammer and compression sub which is secured on its upper end to a multiplier sub which is secured on its upper end to a fourth upper spline sub. In additional embodiments there is provided a spring such as Belleville springs or coiled springs to replace the energizing fluid as well as downward firing tool that can be activated without any external attachment to the wellbore. There is further provided a mechanism for cocking and firing the tool in place of the metering system.