"My Ipad and PC operate from the same router.Can it be that I have transferred Google Earth from my PC to my Ipad thereby removing it from my P.C. "
Absolutely not.
"I follow the download procedure to completion successfully but always fail to establish the facility on screen. "
It's not enough simply to download it. After downloading, it needs to be installed. It would help if you told us what operating system you were running, and which browser you used to download it.