In 1870, the Victorian Permanent Artillery Corps, consisting of about 300 men, was raised. The colony's first permanent, or "regular" unit, it was created to take over responsibility for manning the fortifications that the British garrison had occupied prior to their departure. They were also used to instruct volunteer artillery units. Throughout the rest of the decade, Victoria's military remained roughly the same size, although it obtained higher levels of efficiency as training opportunities were expanded and its organisation was improved. By the time that the British garrison was withdrawn in 1871, the Victorian military consisted of 206 permanent troops and 4,084 militia and volunteers. The following year, the various volunteer rifle companies were re-organised, being placed into battalion-level structures which saw the establishment of two metropolitan battalions, as well as a battalion in Ballarat and another in Mount Alexander. In January 1879, a survey of the colony's military forces determined that there were 228 permanent staff, all of which were serving in the artillery, and 3,202 volunteers serving in the cavalry, engineers, artillery and infantry.