杏吧原创

SECRET mathematical knowledge, ancient astronomies and mysterious monuments are an irresistible formula for hooking our interest in the past. Places like , as well as Mayan temples and the pyramids at Giza, provoke us to ask how these ancient structures were built, and why.

Are we seeking ancient versions of ourselves, or strangers who inhabited a world shaped by something other than modern science? Decades ago, the archaeologist voiced this tension perfectly when she observed that 鈥渆ach age has the Stonehenge it deserves and desires鈥�.

At first glance, Anthony Johnson鈥檚 Solving Stonehenge appears to be a throwback to the 1970s, when the obsessive search for prehistoric geometries, megalithic yards and astronomical alignments was defined by engineer 鈥榮 investigations of Britain鈥檚 prehistoric stone circles. At that time, Stonehenge was clearly an astronomical computer for calculating Neolithic calendars. Thankfully, Johnson has little time for such fancies, apart from the widely accepted alignment associated with the summer and winter solstices. What he seeks are the underlying design principles.

This is an exciting prospect. Yet no less than 172 pages are given over to a history of the monument and its researchers 鈥� from Henry of Huntingdon鈥檚 medieval mention in AD 1130 to today鈥檚 . Up-to-date scene-setting is unavoidable, but this is well-worn territory and made me impatient for Johnson鈥檚 own ideas and theories.

In chapter six he gets into his stride, emphasising that the design of Stonehenge displays repeated geometrical formulae, and highlighting the importance of the numbers 56 (for the , which formed the earliest earth-pit circle), and 30 (for the original number of upright sarsen monoliths). More interesting, perhaps, is the significance of a decorated , discovered in 1808 at the nearby Bronze Age burial mound of Bush Barrow. He sees this as a key to understanding the mindset of Stonehenge鈥檚 designers.

鈥淎 gold lozenge is key to understanding the site鈥檚 designers鈥�

In Johnson鈥檚 eyes, the lozenge鈥檚 beautiful decoration of parallel straight lines and zigzags shows a sophisticated knowledge of form and symmetry in Bronze Age art that was transferred to designs laid out on the landscape. Though this artefact was interred around 1750 BC, at which time Stonehenge was standing in all its glory, he suggests such knowledge was already ancient by that time, so would have been available for the builders of the earlier monument.

I found myself wanting a discussion of Bronze Age art 鈥� and its penchant for miniaturisation 鈥� informed by anthropological insights into the well-documented use of small artefacts to symbolise a grander cosmos. In particular, I was keen to know how the design and symmetry at Stonehenge compare with other sites from the period, including timber circles at nearby and . To what extent is the sophistication of Stonehenge mirrored in contemporary art and architecture?

Around 2500 BC, the builders of Stonehenge may well have had knowledge of geometry from other parts of the world, enabling them to produce right angles, hexagons and pentagons. But culture is serendipitous, and more complex than mathematics. It does not follow natural laws. Knowledge can be lost and modified as well as gained and transmitted. And so, Johnson says, the surveying for Stonehenge鈥檚 two most-recent circles around 1500 BC went badly wrong, and radial accuracy was abandoned.

No one denies that those who authorised Stonehenge had access to mathematical and constructional talent. But archaeologists are rightly wary of ancient geometries 鈥渉idden鈥� in a monument鈥檚 layout. This is especially true when that society is non-literate, and knowledge, experience and technical virtuosity can only be passed on by apprenticeship.

While Johnson鈥檚 innumerable computer-modelled diagrams create an air of scientific authority, readers will have to scrutinise each one and make up their own minds. For me, the author鈥檚 common sense, clear thinking and surveyor鈥檚 eye were ultimately more insightful. Solving Stonehenge is innovative and engaging, and refreshingly free from the lunacies of the past. Whether it reveals the Stonehenge we deserve is another matter.