Were typographical variations between printings of the same journal article common?

Question

In another question, I was asking about the origin of the reduced Planck's constant, $\hbar \equiv \frac{h}{2 \pi} .$ Specifically, I wanted to know why the symbol $`` \hbar "$ was selected for the value $\frac{h}{2 \pi} ,$ where $h$ is Planck's constant.

I found a presentation that claimed it was introduced in a 1926 article:

–Page 17 of "The Planck constant h and the Dirac constant ħ. Their units and their history", by Ian Mills and P. R. Bunker. [PDF]

This seems to make it clear that that article used the symbol, $`` \hbar " .$

However, in checking the cited journal article, it seems to use the symbol $`` h "$ instead.

–Page 1 (printed-page 661) of "On the theory of quantum mechanics", Paul Dirac (1926-10-01). doi:10.1098/rspa.1926.0133.

This would seem to suggest that the presentation claiming that $`` \hbar "$ appeared in the 1926 article was mistaken, if the above screenshot is representative of the 1926 article.

However, as noted in one answer to my question, this article was printed around the time it became possible to use $`` \hbar " .$ So, it seems possible that some printers may've actually used $`` \hbar " ,$ as claimed in the presentation, while the screenshot above shows a different printing that fell back on $`` h " .$

Were such printing variations something that tended to happen in the past? Or, were printings kept more uniform, e.g. done by a single shop in a single go?

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Questions:

1. Historically, have printings of the same journal article contained minor typographical variations?

2. Is there an easy way to check if printings of a particular article had a particular variation between printings? For example, is there an easy way to check if the 1926 article discussed above used $`` h "$ in some printings vs. $`` \hbar "$ in other printings?

Answer 1

Having looked through a number of quantum mechanics papers from the era, it is pretty clear that, as @M.Farooq points out, what Dirac is using in the supposed paper-of-origin is just an italic $h$, which he redefines as Plancks' constant (who originally used the $h$) divided by $2\pi$. So, that is for 1926. In 1931, Dirac is still doing the same thing (see, say, Quantised Singularities in the Electromagnetic Field).

In contrast, in 1931, Oppenheimer Note on Light Quanta and the Electromagnetic Field is explicitly using $h/2\pi$ and not $\hbar$ or $h$ as $h/2\pi$.

By February of 1934, On the Theory of the Electron and Positive, W.H. Furry and J. R. Oppenheimer, Physical Review 45 245 (1934) one gets a real $\hbar$:

By 1937, Dirac seems to have relented (or the editors have insisted) and an $\hbar$ appears in Complex Variables in Quantum Mechanics:

Without spending more time perusing the literature, it is clear that Dirac for some time just preferred to use $h$ instead of an $\hbar$ or $h/2\pi$, thereby redefining $h$ for his purposes. On the American side of the ocean, Oppenheimer shows a change somewhere between 1931 and 1934, moving from $h/2\pi$ to $\hbar$.

Now, all this being said, the answer to the question in the title is a firm No - journal articles were printed and that was that. They would not be reprinted, if at all, for quite some time. Now, Dirac may well have started using $h$ in place of $h/2\pi$, which sets the stage for somebody inventing $\hbar$ to avoid the obvious confusion, but he did not actually use $\hbar$ until later.