I cannot figure out how to interpret the old integration marking below:

This sample is taken from On Riemann's Letters on Analytical Numerical Theory. Is it legal to write it like this:

Hope somebody can help me:) Thank you for advance.
I cannot figure out how to interpret the old integration marking below:

This sample is taken from On Riemann's Letters on Analytical Numerical Theory. Is it legal to write it like this:

Hope somebody can help me:) Thank you for advance.
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