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23 January 2004
E-Bulletin Backscatter
Dendrochronology
Forrest & Brian
Regarding the item on dendrochronology (Science Notebook, Getting Started in Dendrochronology by Forrest M. Mims III, 3 January 2004) and the question on how to preserve a slice of wood. There is a product called Polyethylene Glycol (PEG) available from Lee Valley Tools. PEG is used by wood turners and carvers to prevent their work from cracking or checking. Apparently the process replaces the wood's cellular water with the waxy PEG. I can't vouch for the effectiveness of PEG as I have not had an opportunity to try it.
Lee Valley, also, carries a wide selection of rare-earth magnets in the form of discs, rods, spheres and rings.
Ralph J. Coppola
Circuit Design Web Site
Dear readers of SAS E-Bulletin
I enclose a web site for those want to build the projects I previously described in the E-Bulletin:
www.sas.org/E-Bulletin/2002-04-19/features/features.html
www.sas.org/E-Bulletin/2002-08-09/features/features.html
www.sas.org/E-Bulletin/2002-10-25/features2/features.html
www.sas.org/E-Bulletin/2002-11-22/features2/features.html
www.sas.org/E-Bulletin/2002-12-13/features2/features.html
www.sas.org/E-Bulletin/2003-05-16/features2/body.html
There was a previous web site but it was updated to this site. The new site is http://home.comcast.net/~andrew.g.miller/Eagle/ The URL is case sensitive, so be sure to capitalize the E in Eagle.
Many companies can make circuit boards for a fee. One is Atlas Circuits (P.O. Box 892, Lincolnton, NC 28092, phone 704-735-3943).
Craig Kendrick Sellen
Some spider photos
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Click images to enlarge |
Hi,
When I first got my digital camera this summer with its 3 x optical zoom and close up capability, I was taking pictures of everything and everybody. While sitting on my front steps next to a flower bush I noticed bubble bees busily working the small buds and took several pictures. Then I noticed this yellow thing and several days later, I caught the spider in the act. I am sure this is a common spider found in our pacific northwest but unfortunately I have not classified it (I am a retired chem teacher - bugs are not my forte). I found the spider feasting on a bumble bee. Later I found the spider poised ready to grab another meal. Note - no web. I was able to amplify the photo's a bit with my Windows XP software without much distortion. I proudly showed my photo capture to my friends, and they simply did not give a care!!
Phil Churchley
