Charles
Hope this helps. What you are looking for is a laboratory glass repair company. Here are two I found on the net.

Specialty Glass Incorporated
http://www.specialtyglassinc.com/glassblowing.html

GFI: G Finkenbeiner "This one looks interesting"
http://finkenbeiner.com/repair.htm

LGA: Laboratory Glass Aparatus
http://www.laboratoryglassapparatus.com/glass_services_glass_repair_modification.html

Here's the company I used to have all my glassware made

Southeastern Lab Apparatus Inc.
http://www.sla-scientificglass.com/repair.html

It looks to me like the glass is 1/4 - 3/8th inch pyrex. Like Joe said you might want to cast the resin base and have a few of these made at the same time. Usually they willl give you a better deal on more.

These type of companies love pictures & drawings etc. IF they don't take care of you maybe I can help with this! I have had some serious "Glass Shit" like Doc Brown would say "made up in my day."
Just a Thought

Your BTTF Bud
Ed