Obsidian hydration at high elevation: Archaic quarrying at the Chivay source,southern Peru

We examine obsidian hydration as a means to date archaeological sites at high elevation in the central Andes, and in particular quarry sites that are difficult to date by radiocarbon means. The Chivay obsidian source lies in a volcanic depression above the Colca Valley in Arequipa, Peru (71.5355° S, 15.6423° E) at 4950 masl. We compare obsidian hydration readings from one quarry and two workshop locations. Ninety-one flakes from the quarry pit, and 61 and 33 flakes from the workshops were analyzed for hydration bands. Of these, 68 from the quarry, and 54 and 33, respectively from the workshops produced at least one culturally meaningful hydration band. As expected, obsidian appears to hydrate slowly at this high elevation. Yet, variation in hydration readings is low within stratigraphic contexts, suggesting relatively narrow windows of knapping activities in each excavation level. A small number of radiocarbon dates allow us to develop a preliminary hydration rate for Chivay obsidian in this high elevation location. Hydration data indicate that intensive quarrying began by 3800 cal. BC and stopped ca. 2300 cal. BC. By contrast, the two workshops appear to have been deposited 2900 and 1200 cal. BC, and 2700 and 2400 cal. BC. The data are consistent with an uptick in obsidian use by at least the Terminal Archaic period.     

Correspondence

‘Textual Corruption’     

Visual Motion Illusions,Eye Movements,and the Search for Objectivity

The initial interpretations of motion phenomena are often in terms of eye movements. It reflects a desire to link an objective expression of motion (of the eyes) with a subjective experience of motion. This approach is examined historically with respect to induced motion, motion aftereffects, visual vertigo, autokinetic effects and stroboscopic motion. All but one of these phenomena were initially observed in the natural environment and they have subsequently been studied under laboratory conditions. Eye movements are not correlated with induced motion, the motion aftereffect, or stroboscopic motion, but they do correspond to the direction and extent of visual vertigo. The extent of apparent visual motion in the autokinetic effect far exceeds that of involuntary eye movements but there might be a weak relation between them. If eye movements are to provide a reasonable account of motion illusions then they should apply to all the contours that are visible. This does apply to visual vertigo, but not to induced motion, the motion aftereffect and stroboscopic motion, all of which involve relative motion in a visible display. The autokinetic phenomenon involves the perception of isolated stimuli, and so interpretations in terms of some internal eye movement signals remain sustainable.     

The Neuroscience of Helmholtz and the Theories of Johannes Müller

In this, our continuation paper on Helmholtz and Müller, we examine Helmholtz’s contributions to sensation and perception, with emphasis on his extension and modification of Müller’s theory of specific nerve energies. The material is again presented in biographical-chronological context. We also examine Helmholtz’s views on depth and space perception, and his empirical theory of knowledge, which are also compared to Mutter’s views. It will be shown that Helmholtz remained stimulated by the thoughts and doctrines of Johannes Müller in the sensory-perceptual part of his career, which began early in the 1850s and ended with his death. Nevertheless, Helmholtz’s own experiments and new discoveries by others sometimes led him to quite different conclusions.     

Book reviews

Frontiers

Poststructualist geographies: the diabolical art of spatial science. Marcus Doel. Pp. ix + 229. Edinburgh: Edinburgh University Press, 1999. Price: £45.00 (hbk), £14.95 (pbk). ISBN 0 226 48720 2 (hbk), ISBN 0 226 48721 0 (pbk).

Sleight‐of‐hand

New works in geography

Geography and enlightenment. Edited by David N. Livingstone & Charles W.J. Withers. Pp.viii + 455. Chicago & London: University of Chicago Press, 1999. Price £17.50 (pbk), £36.50 (hbk). ISBN 0 226 48721 0 (pbk), ISBN 0 226 48721 2 (hbk).

Secure from rash assault. Sustaining the Victorian environment. James Winter. Pp. xi + 342. Berkeley: University of California Press, 1999. Price: £ 24.95 (hbk). ISBN 0 520 21609 1.

Perspectives on British rural planning policy, 1994–97. Andrew W. Gilg. Pp. viii + 154. Aldershot: Ashgate, 1999. Price £35.00 (hbk). ISBN 1 85972 641 0 (hbk).

Exploring contemporary migration. Paul Boyle, Keith Halfacree & Vaughan Robinson. Pp. 272. London: Longman, 1998. Price £18.99 (pbk). ISBN 0 58225 161 3.

Focus on Scotland

Urban highlanders: Highland‐lowland migration and urban Gaelic culture, 1700–1900. Charles W.J. Withers. Pp. 271. East Linton: Tuckwell Press, 1998. Price £20.00 (pbk). ISBN 1 86232 040 5.

Girls in trouble: sexuality and social control in rural Scotland, 1660–1780. Rosalind Mitchison & Leah Leneman. Pp. viii + 144. Edinburgh: Scottish Cultural Press, 1998. £10.95 (pbk). ISBN 1 898218 89 7 (pbk).

Girls in trouble: sexuality and social control in urban Scotland, 1660–1780. Rosalind Mitchison & Leah Leneman. Pp. viii + 164. Edinburgh: Scottish Cultural Press, 1998. £12.95 (pbk). ISBN 1 898218 90 0 (pbk).     

Phantom penis: historical dimensions

Interest in sensations from removed body parts other than limbs has increased with modern surgical techniques. This applies particularly to operations (e.g., gender-changing surgeries) that have resulted in phantom genitalia. The impression given in modern accounts, especially those dealing with phantoms associated with penis amputation, is that this is a recently discovered phenomenon. Yet the historical record reveals several cases of phantom penises dating from the late-eighteenth century and the early-nineteenth century. These cases, recorded by some of the leading medical and surgical figures of the era, are of considerable historical and theoretical significance. This is partly because these phantoms were associated with pleasurable sensations, in contrast to the loss of a limb, which for centuries had been associated with painful phantoms. We here present several early reports on phantom penile sensations, with the intent of showing what had been described and why more than 200 years ago.