§ 1. . . A person who sells or keeps for sale, or offers or gives, disposes of or transports any instrument or weapon of the kind usually known as a machine-gun or a sub-machine gun to any person is guilty of a felony, except that the manufacture of machine-guns and sub-machine guns as merchandise and the sale and shipment thereof direct to regularly constituted or appointed state or municipal police departments, sheriffs, policemen, and other peace officers, and to state prisons, penitentiaries and county jails, and to military and naval organizations shall be lawful. § 3. . . . A machine gun is a weapon of any description, irrespective of size, by whatever name known, loaded or unloaded, from which a number of shots or bullets may be rapidly or automatically discharged from a magazine with one continuous pull of the trigger and includes a sub-machine gun. A person who possesses or uses such machine-gun is guilty of a felony. The presence of such machine-gun in any room, dwelling, structure, or vehicle shall be presumptive evidence of its illegal possession by all the persons occupying the place where such machine gun is found.