While some terms of service could extend beyond twenty years, most commissioned ranks were much shorter. Since the Vigiles never achieved the prestige of the Praetorian Guard or the Urban Cohorts, serving in the corps was usually only a means of achieving more honourable and lucrative posts. One known praefectus, Placidianus was put in charge of an expeditionary force sent to Gaul by Claudius II (Gothicus) on his accession in 269 AD to secure the lower Rhone valley against the so-called Gallic Empire. This is the only known instance of the holder of this office being given a substantive command outside Rome. Whether or not his force included vigiles from the city is uncertain. Whether or not the Praefectus Vigilum had his headquarters in any of the stationes identified above or whether he had an entirely separate praefectura is not known. If he is associated with one of the barracks it is likely to have been that of I Cohort in the Via Lata. Duties Fighting fires Every cohort was equipped with standard firefighting equipment. The sipho or fire engine was pulled by horses and consisted of a large double action pump that was partially submerged in a reservoir of water. The Vigiles designated as aquarii needed to have an accurate knowledge of where water was located, and they also formed bucket brigades to bring water to the fire. Attempts were made to smother the fire by covering it with patchwork quilts (centones) soaked with water. There is even evidence that chemical firefighting methods were used by throwing a vinegar based substance called acetum into fires. In many cases the best way to prevent the spread of flames was to tear down the burning building with hooks and levers. For fires in multiple story buildings, cushions and mattresses were spread out on the ground for people to jump onto from the upper levels. A major duty of the Vigiles was to enforce preventative measures against conflagrations. Adequate fire fighting equipment was required in every home. The Digest of Justinian decrees that Vigiles are "ordered to remind every one to have a supply of water ready in his upper room". While the Vigiles only had advising authority, their recommendations were often followed to avoid repercussions for negligence. Corporal punishment was the most common punishment for negligence according to the Digest of Justinian, "where persons have paid insufficient attention to their fire,