"I agre with Ken it is not the letter "H" but sure it is the letter "M" and the maker is for sure Jean Delcour.
the letter M was used for "Manufacture"

If you do like Robert said and hit control and then + many times, you will see that on the top barrel it is an "H". the bottom one looks closer to an "M" but again blowing it up you can see it is an "H"

David