Note: I can't make out the entire brand name ( "Club" ) but both bottles appear to be the identical in style and both are embossed. They also appear to be embossed with the same brand name. Other than the color, the main difference is that one bottle is marked H-3 and one is marked M-11. Also notice that one bottle is clear and one is green. I'm thinking the 291 might be a code number for a standard embossed bottle, but that the clear H bottle was made in 1936 and the green M bottle was made in 1941. ???
H-3 291 ~ Standard - Clear ~ Embossed (Which I posted earlier)
1. The brand? ("Club" something)
2. The embossing?
3. The shape/style?
4. The color?
5. None of the above?
6. Multiples of the above?
7. Something else entirely? If so, what?
In answer to my poll question, I just did a search for Glenshaw seltzer bottles marked with the number 291 and found six examples. (And only six examples) Here's what I discovered about them ...
1. All six bottles are embossed with "Club Seltzer Pittsburgh, Pa"
2. Four of the bottles are green and two of the bottles are clear
3. Each of the six 291 embossed "Club Seltzer" bottles I found had a different Letter-Number code on the base, which were ...
H-3 291 Clear = (1936)
H-10 291 Green = (1936)
H-11 291 Green = (1936)
K-1 291 Clear = (1939)
K-2 291 Green = (1939)
M-11 291 Green = (1941)
Because the bottles with the number 291 are all embossed with "Club Seltzer," I am inclined to believe the number 291 is specific to that particular brand. All six bottles are of the standard type. I did not find a 291 bottle that wasn't a "Club Seltzer" bottle from Pittsburgh, Pa.
Note: I don't have time right now, but when I do I will post some pictures of the 291 "Club Seltzer" bottles I found.
However, I do not think that all of the secondary numbers such as 137, 291, 805, 1284 are brand specific. I will have to take a closer look at them and see what I come up with.
After carefully examining my notes and revisiting numerous image sites, I discovered that the secondary numbers are definitely shape/style codes, as follows ...
137
Every 137 is ... (Non Brand Specific)
1. Standard Shape/Style
2. Green or Clear
3. Either Embossed/Etched/ACL
291*
Every 291 is ... (Brand Specific)
1. Standard Shape/Style
2. Green or Clear
3. Mainly Embossed
(With one green example having an ACL label applied to the non-embossed side)
4. A "Club Seltzer" brand from Pittsburgh, Pennsylvania
805
Every 805 is ... (Non Brand Specific)
1. Multi-Sided
2. Round Shoulder
3. Green or Clear
4. Etched (I have not seen an embossed or ACL example)
1284
Every 1284 is ... (Non Brand Specific)
1. Multi-Sided
2. Flat Shoulder
3. Green or Clear
4. Etched (I have not seen an embossed or ACL example)
*291
I do not know why all of of the 291 bottles are brand specific to "Club Seltzer" in Pittsburgh, Pa., other than to say I haven't found a single 291 seltzer bottle that wasn't marked with that brand.
I have looked at dozens of Glenshaw seltzer bottles and yours is the only one I've seen that doesn't have a letter in front of the number. I don't want to jump to conclusions, but I find it extremely odd that one bottle out of dozens doesn't have a letter in front of the number. I've closely studied the base on your bottle and acknowledge it is marked with [G] and the number 10. All things considered, I have to wonder if the letter part of the mold did not set into the glass for some reason? That sort of thing was not uncommon and there are many examples of that type of occurrence throughout the discussions on this forum site. If I or any other member could find at least one other example of a Glenshaw seltzer bottle without a letter in front of the number, then I wouldn't even be thinking along these lines. But as it stands now, yours is the only example of such a mark that I am aware of. I plan to continue my search a little longer, but have to admit I'm somewhat skeptical of finding another seltzer bottle that's marked like yours.
Take for example the marks on these two bottles ...
H-10 291 - Club Seltzer
Notice all of the marks are boldly molded into the glass.
H-9 1284 - Nehi
Notice the 9 is boldly molded into the glass but the [G] the H and the 1284 are weak. If the H was any weaker we might be talking about a solo 9 mark instead of a solo 10