An 'Imperial Philosophical Machine': The Archaeology of the Cambridge Observatory and Early Modern Science

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Anticipating new construction, the winter of 2008 saw the Cambridge Archaeological Unit (CAU) excavating within the grounds of the Cambridge University Observatory. The c. 200[m.sup.2] site lay relatively high, at c. 23m asl, in West Cambridge, the city's 'bicycle suburb' that developed with the off-college housing of dons during the late nineteenth century (Guillebaud 2007) and which was bordered by University Farm estate (Figure 1; Newman 2008). As open lands on the edge of a major university town, this was a place that 'interesting' things happened, having variously seen the Poultry Nutrition Institute Farm and the Shorts Sebro Ltd Aircraft Repair Works--and, currently, the CAU's offices in what was the Rockefeller Plant-breeding Station (with Wittgenstein and the Darwin family, in the Ascension Parish Burial Ground, nearby neighbours)--and where, even today, fieldwork has to take account of experimental crop-growing regimes.


The site offered traces of a Late Iron Age settlement redeposited in post- medieval quarries, themselves truncated by massive Late Victorian foundations: a sequence which, by normative standards, might be considered a disappointment. But the realisation that the intrusive footings were the remains of the Newall 25 inch refractor telescope--erected there in 1891 and, for a brief time, the largest and most powerful instrument of its kind in the world--entirely recast the results (Figure 2). They provided a platform to address issues relating to both the materiality of early modern science and its coincident local ancestry. A matter of context going, as it were, both outwards and downwards, this paper also briefly overviews recent investigations within the vicinity of the nearby Traveller's Rest Pit quarry and how these reflect upon its still deeper Palaeolithic findings (e.g. Burkitt 1925: xxiv, 54).

The telescope: a temple of science

The site's sequence is readily conveyed by its base-plan (Figure 3). The amoebae-like hollows cut by the telescope's circle are its quarry pits. The imprint of hand-dug extraction, there were essentially two types: small sub-oval pits (0.60-1.15m wide and 0.20-0.70m deep) and larger 'strip' quarries (1.80-3.60m across and 0.35-1.00m deep).


The subsequent telescope-related footings were of poured concrete and rubble. Its main, 12.70m-diameter circle (F. 220)--the trench-built foundation for its dome--being c. 0.80m deep, with the central pad supporting the base of the telescope proper (F. 215/216; c. 2.60m in diameter and 1.30m deep). Prior to its construction, the quarry grounds had been levelled with dumped horizons of sandy silt and gravel, and cut into the top of this, flanking the F. 216 pad, were two 'stop-holes' (F. 201/202). While these might have held scaffolding and relate to the instrument's dismantlement, alternatively, as suggested by Figure 2, they could have been for 'tethering anchors' to secure the instrument during construction. Further concrete foundations were exposed on both the northern and eastern sides of the dome's circle (F. 234 & F. 235), and these must mark ancillary buildings added in the early twentieth century to house further scientific apparatus (Milne 1944: 726). It was the telescope proper that was first erected: the perfection of its bedding being paramount and, in relationship to which, the dome covering was secondary. It was, in fact, crucial that the foundations of the two were separate, so that building subsidence would not distort the instrument itself (see Schaffer, forthcoming a).


Gravel quarrying within the immediate area had ceased by the early eighteenth century, leaving a pitted, almost lunar-like landscape. No longer suitable for arable cultivation, much of the land then appears to have been given to rough pasture (Hall & Ravensdale 1976: 30). …