Articles purchased for the use of or for sale on board any such vessel, as saloon stores or supplies, shall be deemed merchandise, and shall be liable, when purchased at a foreign port, to entry and the payment of the duties found to be due thereon, at the first port of arrival of such vessel in the United States; and for a failure on the part of the saloon keeper or person purchasing or owning such articles to report, make entries, and pay duties, as hereinbefore required, such articles, together with the fixtures and other merchandise, found in such saloon or on or about such vessel, belonging to and owned by such saloon keeper or other person interested in such saloon, shall be seized and forfeited, and such saloon keeper or other person so purchasing and owning shall be liable to a penalty of not less than $100 and not more than $500, and shall be punishable by imprisonment for not less than three months and not more than two years.