The embossing was centered starting in about 1915..
In 1915, the Ball IDEAL was introduced into the line.
(not applied in any way) That being said, let's move on to specifically Ball jars. Ball first started making jars in 1885 in Buffalo, New York.
These jars had the intertwined initials of BBGMCo embossed on them which stood for the Ball Brothers Glass Manufacturing Company.
The very first machine made Ball jar is not positively known, but most likely was either a Balll STANDARD or a Balll IMPROVED MASON. Ball produced many jars with this script style, the Balll MASON jars and ones with just Balll and no other embossing appeared right about the turn of the century. Right about 1910, Ball began phasing out the familiar "shoulder seal" type jars (the cap screws right down onto the shoulder) and went to a new style called a "bead seal".
I see a lot of jars listed on ebay incorrectly with pontil marks. There are only a FEW very early fruit jars which have pontil marks, and these have an applied lip of some kind.
There was no need on any of the screw lid type jars for attaching a punty rod to the base of the jar (which creates the pontil mark) because the thread area and lip was created in the mould when the jars were made.
The beautifully embossed "Christmas Mason" jars were produced right around 1890.
About 1892 and probably even earlier, Ball began adding their name to some of the 1858 type jars, some on front and others on the back in all block letters.
The lip of the one with the C bump is very rough and the lower seams don't line up with the seams on the jar's top.