On last note on window glass:

Jonathan Weiland has a nice review of thickness measurements of window 
glass on SHA website:

Weiland, Jonathan
2009 A comparison and review of window glass analysis approaches in 
historical archaeology. Technical Briefs in Historical Archaeology 4: 29–40.

Cheers,
Ben Carter


On 2/20/2010 10:54 AM, Conrad Bladey wrote:
> Long long ago,,,,it seems....when I last worked with things (still 
> recovering from political Burnout).....
> I was quite excited about the measurement of what I called at the time 
> "essential material attribute description"
> Essentially measuring artifacts in a way that procedures such as 
> calculous could be done on them as opposed to shard counts which are 
> only good for accounting for things....
>
> I decided then that volume measurement and maximum and minimum lengths 
> should be always calculated and included in all reports.....(of course 
> part of the burn out was caused by neglect of this idea...oh well sop.)
> In the course of this work I found taking volume quickly by water 
> displacemnt worked well especially on non porus objects. One can use 
> container with spout or graduated cylinder for larger quantitie or 
> combination of both. This does not take long. to avoid liquids one can 
> use fine sand.....
> I also came to the conclusion that as in soil science screens of 
> different sizes could be employed to size sort if one wanted some idea 
> of the narrowest hole something would go through and did not want 
> shortest and longest mesures.
> For volume and maybe even for size I found that the means to measure 
> this was already available on a conveyor belt quick system- lasers- 
> used by UPS and shippers to quickly measure volume of packages
> then important for loading trucks as it is for understanding relation 
> of artifact to behavior
>
> Glass like everything else plays many roles only one of which is in 
> the bottle or window- I know....I have several times now had to watch 
> for weeks as glass shards in the feet worked their way up- ouch!
>
>
> So my friends confronted by loads of flotsom and jetsum requiring 
> measurement a few quick an easy solutions. Takes time but leaving 
> proper discription out renders reports less helpful in the long run.
> Have fun.
>
> Conrad Bladey
> [log in to unmask]
> http://www.cbladey.com
>
> Benjamin Carter wrote:
>
>> Dear all,
>>
>> Thank you all very much for your information, especially to David 
>> Moyer for the extensive bibliography.
>>
>> You will all have to forgive me for my faux pas of calling my 
>> "window" glass by the incorrect term of plate glass (Doesn't the term 
>> "window" predetermine function? Are there other functions for 
>> "window" glass than for windows?). Irregardless, I will use window 
>> glass from now on.
>>
>> I was aware of Moir's equation, etc... but it is inappropriate for 
>> these contexts as they are mostly surface, the sample size not large 
>> enough for statistical significance and this is a preliminary report. 
>> To spend all that time measuring shards of glass would not be well 
>> spent. I am happy to spend time in such an enterprise- I spent 
>> thousands of hours measuring nearly 10,000 shell beads and 1000 
>> lithic drills for my dissertation. Such an expense would not be 
>> productive in this case.
>>
>> I was hoping that there was some big change in glass technology that 
>> occurred where "window" glass went from having a colored cast (aqua, 
>> etc.) to being very clear. I assume that transition happened when 
>> decolorizing agents were used. Bill Lindsey (on the bottle 
>> identification website within the SHA website) indicates that 
>> decolorizing is quite old- 15th century, but he also appears to 
>> indicate that decolorizing bottles was not common until the late 19th 
>> century into the 20th century. That, of course, is in reference to 
>> bottles, what about window glass?
>>
>> Was there a point in time when decolorized glass become much more 
>> prevalent?
>>
>> Overall, I have to admit that this is not a large issue for the 
>> particular report that I am working on right now. If it was, I would 
>> have spent much more time working on it myself. I sent the message to 
>> Histarch in the hopes that there was a small, but important detail 
>> that I was missing. Alas, I have not heard much on that point, though 
>> there is likely something in Moyer's bibliography.
>>
>> Thanks again for all the help and if anyone has more info on 
>> decolorized window glass or anything else, I'd love to hear more.
>>
>> Cheers,
>> Ben (not Bob) Carter
>>
>>
>> On 2/19/2010 12:51 PM, Doms, Keith wrote:
>>
>>> Dear Bob,
>>> I use the term plate glass for the automated, thick poured glass
>>> that started to be produced in the late 19th C. Yes, Dederot shows
>>> plate glass manufacture in France in the 18th c. But that plate glass
>>> was almost solely for mirrors. I use the term window glass is used for
>>> the thinner domestically used glass regardless of its manufacture.
>>> The bluish or aqua glass is not soda glass. Soda glass is clear
>>> and typically develops a white patina after being buried or submerged.
>>> The aqua color comes from iron in the sand which is used to make the
>>> glass. The more iron the greener the glass.
>>> Regarding glass thickness and dates, Grant Day (2001)claims to
>>> have used it successfully in dating a different parts of a 19th C. site
>>> using the regression formula of Moir (1977). "84.22x (Glass 
>>> thickness in
>>> mm)+ 1712.7". I have problems with this as I have measured a number of
>>> large window glass fragments from a nineteenth century site only to 
>>> find
>>> that the thickness varied noticeably across each fragment. Also, I have
>>> not seen background research to indicate how standardized window glass
>>> thickness is at a given time period. Even today, you can get different
>>> thicknesses of window glass at hardware store. Guess what, the thinner
>>> glass is cheaper. There is a good chance that if a window pane is
>>> broken, it may not get replaced with the same thickness of glass. This
>>> is one reason that some windows rattle.
>>> I do not know of any publications that indicate when clear flat
>>> glass was first produced. Remember, clear glass in the 18th C. was hard
>>> to achieve and therefore more expensive and limited in use. Clear flat
>>> glass could also be from furniture and mirrors. Today both clear and
>>> aqua window glass is available. There are photographs of English 17th
>>> century windows with five or six different shades of almost clear to
>>> aqua to green window panes. (Noel-Hume 2005)
>>> If the window glass fragments are large enough you might be able
>>> to find the distinctive marks indicative of crown glass or tube glass.
>>> Unfortunately, both processes were in use during you site's occupation.
>>> I believe that distribution analysis is still the best and most
>>> reliable analysis that can be performed on window glass
>>>
>>> I don't mean to be snarky, but doesn't any teach this basic
>>> artifact information any more?
>>> Day, Grant
>>> 2001 Window Glass Dating: When was McConnell's Homestead Built? Paper
>>> presented at the 4th Annual South Central Historical Archaeological
>>> Conference, Little Rock, AK
>>>
>>> Moir, Randall
>>> 1977 Window Glass: A Stistical Perspective. Manuscript on file,
>>> Archaeology Research Program, Southern Methodist University, Dallas, 
>>> TX.
>>>
>>>
>>> Noel-Hume, Ivor
>>> 2005 A Window on Williamsburg. "Something from the Cellar". Colonial
>>> Williamsburg Foundation.
>>>
>>> -----Original Message-----
>>> From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of
>>> Benjamin Carter
>>> Sent: Friday, February 19, 2010 9:09 AM
>>> To: [log in to unmask]
>>> Subject: Plate Glass references
>>>
>>> All,
>>>
>>> I am having a bit of trouble finding references for the dating of plate
>>> glass.
>>>
>>> There are, of course, far too many resources for bottle and table 
>>> glass,
>>>
>>> but I haven't had much luck finding out any details about plate glass.
>>>
>>> I have mostly plate glass with a bluish cast, which I assume is soda
>>> glass. But, I also have, from the same contexts, some extremely clear
>>> plate glass. Why are these different? I assume that 'decolorizing'
>>> agents were use for the clear glass. Is there a time when this began.
>>> The site is fairly well dated- 1790s-1811. Would a change in glass 
>>> types
>>>
>>> have happened at this time? Or, is it likely that the clear glass is
>>> intrusive. Many of my contexts are fairly close to the surface.
>>>
>>> Cheers,
>>> Ben Carter
>>>
>>
>>
>