In addition to the responsibility, already mentioned, of issuing to schools the syllabuses that make up the primary-school curriculum, the Department of Education has the further task of helping teachers to cover the work prescribed. One of the major duties of inspectors of schools is to give positive guidance to teachers on classroom work. For certain subjects — namely, physical education, art and crafts, nature study and science, reading, and music — specialist advisory services are available to give advice and practical help. Advisers to junior classes — a small group of experienced teachers of infants — are able to help teachers over the whole range of primer work. Members of the advisory services, themselves experienced teachers, give expert guidance to classroom teachers in need of help, assist head teachers and their staffs in drawing up suitable school programmes, and conduct courses of in-service training. In some country areas rural schools advisers regularly visit small schools to help teachers with their programmes. Textbooks, journals, bulletins, and handbooks reach the schools from the Department's school publications branch, while the National Film Library is a source of films and filmstrips. In the four main centres the museum education officers receive groups of pupils at the museums with the aim of supplementing classroom studies in a vivid, practical way. In order to assist in bridging studies in science and mathematics between primary and post-primary schools, an officer for school science and an officer for school mathematics have been appointed. The arrangement of in-service courses is a further means of helping teachers with the curriculum. This is a responsibility in which teachers have willingly shared, and the Teachers' Refresher Course Committee has for many years organised voluntary national holiday courses annually. A highly important development in in-service training was the opening in 1961 of Lopdell House, the Department's residential in-service centre, at Titirangi.