Constructed in 1828 to process the wheat and corn crops of the Moreton Bay penal settlement, it had a treadmill attached for times when there was no wind but also as a tool for punishing convicts.

[1] In May 1825, after eight months of occupation at Redcliffe, the contingent of convicts, soldiers, administrators and their families comprising the Moreton Bay penal settlement relocated to the site of present-day Brisbane's central business district.

The growing settlement was to be self-sufficient in feeding its residents by cultivating corn (also known as maize) and wheat crops at the government farm, which were then processed into meal and flour by hand mills.

Commandant Patrick Logan indicated at this time that such a device at Brisbane town would be of service and also provide an avenue for the punishment of convicts.

[1][9] The treadmill was an important component of the mill, for use as punishment without trial, and for times when there was no wind but the amounts of grain sufficient to sustain the settlement still required processing.

No plans exist of the Brisbane treadmill; however, the Office of the Colonial Architect produced a standard Design for Tread Mill Adapted for Country Districts Average Estimate £120.

[11][12] The first casualty of the treadmill, which produced the first official record of its existence, occurred in September 1829 when prisoner Michael Collins lost his life after being entangled in the operating mechanism.

This was approved in 1840-41 but it continued to sporadically process grain until 1845, when due to crop failure, a stagnant population and the availability of imported flour, it finally ceased being used.

[1] Indicative of the prominence of its physical position, the tower served as one of the stations for the trigonometrical survey of the Moreton Bay district conducted by Robert Dixon, Granville Stapylton and James Warner from May 1839 in preparation for the area being opened to free settlement.

The local Foreman of Public Works, Andrew Petrie, converted the disused structure into a gallows by running a beam out of the upper window to which was attached the nooses.

The condemned were two Aboriginal men named Mullan (also known as Merridio) and Nungavil (also known as Neugavil), who had been convicted in Sydney of being accessories to the murder of Assistant Surveyor Granville Stapylton and one of his party near Mount Lindsay on 31 May 1840.

[29] In a January 1850 article the Moreton Bay Courier continued its appeal for the windmill not to be pulled down and secured by the town, arguing that aside from its landmark and picturesque qualities it was the "best fixed point for land measurement in the district".

The renovations were undertaken by John Petrie in October 1861 to plans by colonial architect Charles Tiffin and included the removal of the windmill stocks or arms and wheels; the laying of floors on each storey; new doors and windows; a weatherproof floor on the top of the tower with an iron railing; a new winding staircase from bottom to top; repair of stone, brickwork and plastering; and the installation of a high flagstaff to fly signals.

[31] A cottage for the signalman was constructed in 1883 to the immediate west of the tower to plans prepared by Government Architect FDG Stanley and on part of the Waterworks reserve.

[1] On 20 January 1862, the Old Windmill became the first home of the newly founded Queensland Museum; serving this purpose until 1868 when other accommodation was provided in the old convict barracks or parliamentary building on Queen Street.

The Tower was ideally suited for this purpose as it commanded a panoramic view from Moreton Bay in the east, to Darling Downs on the western horizon.

Some restoration work was carried out in 1950 on the advice of Frank Costello (then Officer in Charge of Planning and Building with the City Council), which included removal of old render and re-rendering the entire structure.

[1] In 1982 City Council undertook some external maintenance work on the observation house or cabin, including replacement of deteriorated timber to the balcony and sills, and corrugated iron on the roof, and repair of the time ball and its mast (which was shortened by about 300 millimetres (12 in) to remove some part affected by dry rot).

[1][40] In 1987 a consortium of companies involved in the construction of the Central Plaza office building offered to assist the Brisbane City Council with the conservation of the Windmill Tower.

In all, the investigation resulted in Nickell stating that the stories of the Tower Mill hauntings are the work "of some percipient's faulty imagination or the creation of a writer of fakelore.

Excluding the time ball and its mast, it stands at about 16 metres (52 ft) in height on Wickham Terrace in Spring Hill, overlooking the modern office towers of Brisbane's central business district.

The rear reserve boundary marked by a hedge adjoins that of the Spring Hill Reservoirs, the three gable roofs of which nestle below the park lawn.

A single-level observation house and platform surmount the tower with a riveted copper time ball and painted hardwood mast projecting above it.

[1] On the windmill tower's interior the single volume spaces of each floor are punctuated by the hexagonal stair which connects the ground with the observatory house.

[53][1] The grounds surrounding the tower are grassed and sparsely landscaped and although there are no visible surface remnants, are likely to contain subsurface archaeological evidence of the use of the site over its entire history.

[1] Archaeological investigations at the Windmill Tower have the potential to contribute important new information about actual treadmill design and construction techniques, early punishment practices employed in Moreton Bay, the domestic conditions of mid to late nineteenth century Brisbane through artefact analysis, as well other previously unknown or undocumented uses of the windmill tower site.

[1] Archaeological evidence of the treadmill would illustrate nineteenth century punishment practices and the necessity of technological solutions for the grinding of enough grain to feed the fledgling settlement.

Despite subsequent city development obscuring or entirely obliterating the views to it from other parts of the area, the windmill tower is still strongly evocative and symbolic of Queensland's convict past, one of its key periods of significance.

The use of the Windmill Tower as a signal station from 1855 demonstrates an aspect of innovative technology to develop a system of communication linking semaphore and electric telegraph to relay shipping news to the settlement.

The Windmill Tower has a special association with the Brisbane and Queensland communities, serving as an important landmark and being a tangible and symbolic representation of European settlement of the state.