(1)No licensed wholesale or retail vendor of potable foreign liquor shall reduce the strength of such liquor whether by the addition of water, or by mixing it with liquor of a lower strength or by any other means whatsoever, unless he holds a special licence authorising him to do so :Provided that this prohibition shall not extend to the admixture of beer or spirits, as the case may be, of different strength by a licensed brewer or distiller in so far as such admixture is permitted by the rules made for the regulation of breweries or distilleries.
