Until 1931 a ball that bounced over a fence was a home run. I looked for both Bounced HR and IPHR (inside the park home runs). Some quick comments:
In 1909 Ty Cobb won the triple crown, leading AL in BA, RBI, HR. All 9 of Cobb’s HR were IPHR. Frank Home Run Baker hit four HR, three of which went over fences to lead the AL.
In 1913 in NL Gavvy Cravath of Philadelphia beat teammate Fred Luderus 19-18. However, Cravath hit one IPHR and FIVE Bounced HR: only 13 over the fences. Luderus had one IPHR and two Bounced HR: 15 over the fences.
OK, you see how it works. The most recent occurrences of HR leadership being impacted by HR not over the fence: 1984: Dale Murphy (Atlanta) one IPHR tied Mike Schmidt (Philadelphia) at 36 1982: Dave Kingman one IPHR beat (Mets) Dale Murphy (Atlanta) 37-36 1980 Ben Oglivie (Milwaukee) two IPHR tied Reggie Jackson (Yankees) at 41.
Going back to 1903 Cobb was the only player I found to lead the league in home runs without hitting any over the fence. It is also the only season in which Cobb led in home runs.
By now you must be wondering: hey, wait a minute, you mean that Babe Ruth piled up many of his 714 home runs by bouncing them over the fence? Amazingly, the Babe supposedly never hit a bouncing home run although he did hit ten IPHR. In 1927 number 27 of 60 was IPHR. Does that change your view of the Babe’s achievement?
Does any of this change your views of their accomplishments? How about this? Another home run rule was changed after the 1930 season. In addition to banning the bouncing home run, which helped boost home run totals, although not for Ruth, the curving rule was also changed.
The ball can curve quite a bit when hit down the foul line. It hooks to the pull side and slices to the opposite side. Before 1931 a long fly was judged to be fair or foul by where it landed, not where it was when it passed the foul pole as is the case now. We see now many home runs land foul after curving past the pole. Back then those long fly balls were simply long fouls. In 1927 Ruth hit number 60 down the right field line in Yankee Stadium. Some thought that the ball curved and landed foul well past the pole and that it was not a home run. Did the Babe get the benefit of the doubt?
So the curving rule hurt home run hitting before 1931 when Ruth played most of his career (88% of plate appearances). It probably hurt more than the bouncing rule helped but we’ll never know.
Does that additional bit of information change your view of the career home run leaders?
From 1884 through 1919 a walk off home run counted as a home run only if it was the winning run. If the winning run was already across the plate then the batter received credit only for the number of bases he had reached, much like a long walk off non home run today. Supposedly 40 hits were not home runs that would have bee home runs after 1919. I do not know if Ruth lost any home runs.
Through the looking glass it gets curiouser and curiouser.