On Mon, 4 Apr 2016 22:08:23 -0500, Rene lamontagne
wrote:

On 4/4/2016 8:20 PM, Paul in Houston TX wrote:
Paul wrote:
(snip)
Years later, when I went to the store, the cup had
been replaced by "political correctness". A monstrosity
was available, also in Pyrex, and it's two cups in size.
This is a picture of a thing to waste cupboard space.
The cooking cup amount is circled in blue.

And Pyrex has not been made of expensive borosilicate since at least 1998.
It's now garbage soda-lime that breaks when exposed to changing
temperatures.

I used a lot of Real Pyrex mirror blanks for amateur telescope making
from 1964 to 1975, in the following sizes.

4 1/4 Inch x 3
6 inch x 3
7 inch x 3
8 inch x 1
12 1/2 inch x 1
a total of about 11 mirrors
thickness varied from 1 inch to 2 1/2 inches These were Corning Glass
pieces.

Rene

Here is an interesting article from Smithsonian Magazine about Pyrex:

http://www.smithsonianmag.com/innova...955513/?no-ist