Comptes rendus de l'Académie des Sciences by Ciro Santilli 34 Updated Created
Apparently there were biweekly reports, that were grouped and published biannually on January and July, each one with a sequential tome number.
For example, both Marie Curie's Polonium paper and Marie Curie's Radium paper were published in the second half of 1898 and fell in tome 127.
TODO how to download a PDF from? I can't even turn the pages...