There are two possibilities:
H Hartman - Schoonhoven 1889 - 1910 or
H Hooykaas - Schoonhoven 1906 - 1924
The last made many silver miniatures and if I observe the poor casting of this little man with the pipe I would suggest Hooykaas as the silversmith
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The site you refer to is certainly not complete.
If you look it up in hallmarks dictionairy of the Netherlands (Meestertekens 1813 - 1963) there is also an exact match (no 4485 on page 225) for H Hooykaas.
I do collect dutch miniatures. I have never seen a miniature by Hartman and so many by Hooykaas.
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