The fact that any slot machine or punch board is set up, operated, conducted, displayed, or exposed in a public place for any considerable length of time, provided the time and place is sufficient to put a reasonably efficient officer upon inquiry and notice, this shall be received along with other evidence in proving that the sheriff and district attorney of the county and the constable and policemen of the district, city or town where the same occurred had knowledge of the same.
Laws 1939, p. 12, § 12.