Rhind Lectures: [Edinburgh]
23 June 2018
Dr John Barber will give the Rhind lectures in Edinburgh this year on the them of technical engineering capacities of prehistoric builders of large Neolithic and Iron Age structures. The six lectures over the 3 days are free to the public. Further details on the Society of Antiquaries of Scotland website.
‘Drystone technologies: Neolithic tensions and Iron Age compressions’
Dr John Barber MA, BA, FSA, FSA Scot, MCIfA
The technical engineering capacities of prehistoric builders of large Neolithic and Iron Age structures are intriguing. Invasive introduction has been the favoured explanatory mechanism for structural innovation in these islands, rather than the converse appeal to domestic design genius. However, drystone engineering so constrains the builders’ design ambitions that similar structures result from the limitations of the technology more than from the social interconnections of their builders. These lectures explore the interplay of technological capacity and design freedom in prehistoric Scotland.
John Barber was born in Cork, Ireland, in 1947 and graduated from University College Cork, before going on to a career in archaeology. He recently graduated with a PhD in Architecture at the University of Edinburgh, building upon two decades of specialist interest in large drystone-built structures in Western Europe in general and the British Isles in particular. Between 1976 and 1992 he worked in what has now become HES before leaving it to found the AOC Archaeology Group, of which he was managing director until 2011. In the recent past he has excavated, mainly for conservation purposes, elements of three Neolithic chambered cairns and was involved in the excavation of five brochs. He is currently involved in the excavation and conservation of brochs like Clachtoll, Castle Grugaig and others. In developing approaches to these monuments, he has also re-constructed cairns and brochs and their compositional elements at scales ranging from 1:50, to 1:1, to study their stability issues and decomposition mechanisms.
Friday 22nd June 2018
6.00pm The urge to build: invariant and canonical forms: pathways to decomposition
Exploring the role of instinct and instinctual behaviours in building as a counterbalance to the social determinism of many current narratives; the forms of categorisation used in archaeological and architectural studies are considered, distinguishing between abstract narratives and real-world observations. Strongly canonical monument forms are not only constrained in their original design, but also influence the nature of their subsequent anthropic modifications and predetermines some pathways to decomposition, while ensuring that the form of the original structure may be discernible even following millennia of use and abuse of the monument. Finally, some technical issues affecting drystone building are introduced and the relationship between the concepts of monumentality and engineering efficiency are discussed.
Followed by a Reception
Saturday 23rd June 2018
Corbelling, the horizontal arch and polycope walls in the construction of loose fill monuments
Addressing the specifics of drystone building, this lecture will first explore the probable commodification of stone during the Neolithic. Using Neolithic chambered cairns it will set out the engineering challenges of constructing chambers and the difficulty of identifying the chronological implications of deformation and evidence for re-construction and later reuses. Monuments, sensu memorialising, as opposed to monumentality, sensu Alois Riegl’s ‘age value’ will be considered. Similarly, the interrelationships of monumentalising and aggrandising, on the one hand, and of canonicity and mutability of the other are further considered.
Spandrels: architecture as an unintended consequence of engineering
John Ruskin considered architecture to comprise all the parts of a structure that were not necessary for its structural integrity, the rest was merely ‘building’ [or ‘structural engineering’]. In building an archway within a rectangular frame, two vaguely triangular areas are excluded in the upper left and right corners of the rectangle; these are the spandrels. These by-products of construction became available for architecture, for social manipulation, and were highly decorated over time. In Neolithic chambered cairns, the primary structural challenge of the entrance passage produced a range of engineering solutions which created spaces and structures that, like spandrels, became available for acculturation.
Towers in drystone construction
The evolutionary theorist S J Gould asked what the evolutionary value of complex structures like wings and eyes might be, and the question may be applied to the drystone-built broch tower. There is no evolutionary or developmental potential for gradualist formation of a 15m high tower. This assertion will be explored via a revision of the paradigmatic ‘standard model’ broch. A structural analysis of the broch tower model reveals its strengths and weaknesses, but more particularly reveals essential structural assemblies that never existed before towers were built. It will be argued that these present us with evidence for unique acts of Iron Age creation, possibly even of architectural engineering genius.
Sunday 24th June 2018
Full fathom five; the repair, rebuild, reuse and abuse of brochs
Gurness and Midhowe exemplify the scale of modification of broch towers and their chimerical nature as excavated for public presentation will be laid out. Thrumster broch will present evidence of sequential and significant re-modelling over time, paralleled elsewhere, and the broch at Clachtoll was probably abandoned before the mid first century BC by which time it had already undergone at least one, and probably more, significant structural failure episodes. Despite the observed high levels of mutation and destruction, it can be confidently argued that the original monuments have been constrained in their scales and their form almost unswerving from a ‘standard model’ updated for this study. The consequences of the complex diachronic nature of these monuments present particular difficulties for their interpretation, conservation and presentation, some of which will be exemplified from current work.
The economics of tower building; ‘For which of you, intending to build a tower, sitteth not down first, and counteth the cost, whether he have sufficient to finish it?’ Luke 14: 28-30.
Agricultural surplus, widely held to be the foundation of economic systems, will found an economic model that could represent a generic Iron Age social context. By establishing a yardstick for the measurement of construction effort that is keyed to the simple physics of lifting and moving mass, we can assess the ‘building costs’ for building brochs of varying scales. Accepting modern studies of the constant operational rating of human beings, the scale of effort can be converted to the minimum numbers of person-days required to build the monument. The ‘energetics’ commodification of human effort provides a common currency in which the relative values of Iron Age broch towers and Neolithic chambered cairns can be considered.