asha

ASHA NEWS

ARTEFACT OF THE MONTH: Bullseye! Pontilled Window Glass


Bronwyn Woff, Research Associate, La Trobe University

The fragment of glass illustrated in the images below was found in the 1988 excavation season of Melbourne's Little Lon district. This area was reported to be a slum, with a mixed use of domestic and light industrial lots.


Crown glass window pane fragment. LL71844 Historical Archaeology Collection, Museums Victoria. Images: Bronwyn Woff

The glass fragment is the central panel of a spun crown glass sheet, which was created in the manufacture of glass for window panes. Hot glass was spun on a pontil rod so that it slowly spread into a large disc up to 1400mm wide. Because of this manufacturing technique, the glass was thicker at the centre than at the edges. The majority of glass imported to Australia from Britain before 1834 was manufactured in this way, as taxes and duties were lower than for other manufacturing techniques (Boow, 1991 pp.100-102). This glass fragment can be dated to between 1788 and the 1860s (Boow, 1991 pp.100-104).

Crown Glass being spun flat by glass makers. Image from “Glass in Architecture and Decoration” by Raymond McGrath & A.C. Frost, 2nd Edition, London, 1961 [1937], p. 75 via : https://blog.mcny.org/2014/11/25/whats-in-an-artifact-crown-glass/    (accessed February 28, 2017.)

In this case, the whole sheet was used and the central section was cut into a pane of glass with the "bulls eye" pontil mark in place. In some cases, these were ground out or otherwise modified so that the pontil mark was not evident, but in this example the snapped off pontil mark protrudes at least 5mm from the flat glass. One straight-cut edge of the window pane is present on the shortest side. Because of the flaw present in the glass, this window pane would have been much cheaper to purchase than a thin, outer fragment and this may reflect the buying power of the owners of the residential property where it was found at Little Lon.

 


"Spectactular clear bullseye glass panes in an English house" via: http://www.peachridgeglass.com/2012/04/the-bulls-eye-glass-pane/  (accessed February 28, 2017)


Bronwyn is currently working as a subcontracting archaeologist, cataloger and analyst. She is contactable via: bronwyn_woff@outlook.com.au