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29 minutes ago, blue_dolphin said:

Could be hard to track down exactly as household measurements were barely being standardized in the late 1800s.  This publication, Correct administration aid for oral liquid medicines: Is a household spoon the right choice? says

which suggests there may have been other equivalents in use prior to then which seems to be the age of your glasses. Unfortunately, the online version of the reference they cited for that seems like it might be the wrong page or something so I wasn’t able to get anything further. 
 

They are an interesting little collection though!

I think its figured out now but you are right about standardized measurements.  I've read or someone told me that In the old west, shot glasses were not standardized for quite a while, nor were whiskey glasses.

28 minutes ago, blue_dolphin said:

Could be hard to track down exactly as household measurements were barely being standardized in the late 1800s.  This publication, Correct administration aid for oral liquid medicines: Is a household spoon the right choice? says

which suggests there may have been other equivalents in use prior to then which seems to be the age of your glasses. Unfortunately, the online version of the reference they cited for that seems like it might be the wrong page or something so I wasn’t able to get anything further. 
 

They are an interesting little collection though!

I think its figured out now but you are right about standardized measurements.

ve read or someone told me that In the old west, shot glasses were not standardized for quite a while, nor were whiskey glasses.