The regular and special reports of the survey, with proper illustrations and maps, shall be printed as the director may direct, and the reports shall be distributed or sold by the director as the interests of the state, the diffusion of practical information relating to the development of the state, and the advancement of science, may demand. All moneys obtained by the sales of the reports may be used to defray the costs of publication and their distribution to the people, and any balance may be retained for that purpose.