The Sydney Opera House Car Park and The Double Helix
   
The Sydney Opera House Car Park records the serendipitous design of the unique underground car park of the Sydney Opera House. This 1,100 car facility was built 20 years after the opening of the Opera House, during which period patrons had to walk significant distances from various parking places within the central business district.

Using the Opera House Car Park story as the starting point, the author sets out to discover when, and where, mankind first used the elegant shape of the double helix in architecture and engineering. This journey of discovery takes the reader through France, Italy, ancient Greece, Egypt, Afghanistan, and finally to the postulated first use in Babylonia. The author also documents, in an Appendix, many of the disparate uses of single and double helices, in ancient and modern pumps, screws, springs, and the Boomerang Propeller of Sir Thomas Mitchell.

In June 2013, Adrian Smith of PSM gave the author the following photographs of a very interesting Dutch design, dating from 1875, combining a windwill with an Archimedean screw pump.

The description is as follows:

Purchase details
   

Small wind-driven drainage mill, Wouterswoude (Fr.), ca. 1875

Relocated: 1928

A mill on rollers

In this simple meadow mill, known locally as a 'tjasker', the sails drive the sail axle. Behind the sails is the brake wheel with the brake. Attached to the axle is an Archimedean screw that rotates in a barrel. The Archimedean screw raises the water, which then flows out of the dike via a wooden gully. The fact that the mill is on rollers means that it can turn to face (almost) all wind directions. Numerous 'tjaskers' were built in the north-eastern Netherlands up until 1930. Sometimes these meadow mills were partially dismantled over the winter and then rebuilt in spring. So that the water that the mill raises does not go to waste, at the museum it flows back into the reservoir. In reality the water was of course drained from the land.