four years, of which (in the Army) the first twelve in the line and the last twelve years with the reserve. Those desiring to be school-trained officers and have the required fitness for service may enter for training at a military school before the ordin- ary age of enrolment. In respect of service they join the year-class to which they belong. For other volunteers the period of service counts from January 1 following their acceptance for service, yet not earlier than January 1 follow- ing the completion of their 18th year. All men liable for conscription, provided they are not found altogether ineligible, shall be enrolled in the year in which they attain the age of 20 years, or in the next succeeding year in which enrolment can take place. The period of service shall count from January 1 of the year following enrolment. Conscripts enrolled for the Army are called up for service in the recruit school in their first or second conscript year. In each war-levy the younger year-classes are called up before the older ones, excepting, however, the first year-class of the line troops. Naval Defence. As re-organised in 1933 the Naval Defence of Norway consists of the Navy proper, the Naval Air Arm, and Coastal Artillery. 40