In the article you linked, it says: "Tome XV, Vingt-quatrieme cahier, 1835", i.e., 

> Tome 15, Cahier 24, 1835

Then we find [two][1] [more][2], for;

> Tome 15, cahier 25, 1837, and

> Tome 18, cahier 30, 1845

So, **it seems like there are a few cahiers for each tome.**

Since this is a different system than modern Anglophone publishing, I would keep "tome" and "cahier" untranslated in the bibliography. If this is not possible, I would treat cahier as issue and tome as volume, since in English, there are several issues for each volume. 




  [1]: https://books.google.com/books?id=XGc_AAAAcAAJ&pg=RA1-PP5&dq=journal%20de%20l%27ecole%20polytechnique&hl=en&sa=X&ved=0ahUKEwjhpNTk_szgAhUCON8KHb-oCc8Q6AEIKzAA#v=onepage&q=journal%20de%20l'ecole%20polytechnique&f=false
  [2]: https://books.google.com/books?id=G1E5AQAAMAAJ&pg=PA2&dq=journal%20de%20l%27ecole%20polytechnique&hl=en&sa=X&ved=0ahUKEwjhpNTk_szgAhUCON8KHb-oCc8Q6AEIMzAB#v=onepage&q=journal%20de%20l'ecole%20polytechnique&f=false