Behind the Commissioner's Offices on Main Road Laxey is a small brick building which houses some fascinating early electrical technology. Inside are cabinets which contain a set of Mercury Arc Rectifiers. They were installed in the 1930s to convert the newly available AC current from the Island's supply to the DC current required to run the railway. The large glass bulbs contain mercury through which the current passes, making the liquid bubble and spark. The process converts AC to DC. The rectifiers are reminders of a bygone age - nowadays such conversions are carried out by solid state rectifiers.