He shall summon the county superintendents, or the city superintendents and district principals of graded schools, of each judicial district, or of two (2) or more districts combined, to meet jointly or separately at such time and place as he shall appoint, giving them due notice of such meeting. The object of such meetings shall be to discuss school organization, school supervision, and such other matters as may properly come before such meetings.
The term "district principal" means the head teacher of a graded school of four (4) or more teachers, but smaller than a class A independent district school, whether such school be maintained under article 3 or under article 4 of chapter 41 of Idaho Compiled Statutes.