help ID this item fuel/oil/pitcher/scale?

HI GUYS! Im Nick and new to this Forum...

I came Across this Item at the Swap Meet in San Diego.
I got it because it looked like it belonged in my garage and I thought it may be related to Fuel or something....
I have no idea what this is, or anything I researched the names and didn't get anything and its been on the back of my mind to figure it out.
my neighbor is a retired mechanical engineer and was stumped as well.

On finer details the glass tube (sight gauge) seems to have a green hue to it with a slight etching that states: "Moncrieffs Perth Scotland".
also on the metal plaque on the very bottom it says Boyle Manufacturing CO " Los Angeles Almeda"

 

thanks! as I was doing research here is a picture of the United States Steel Products Company with the (boylecompany) logo on the right.
maybe thats a clue...
@Ineedhelp:thanks!

 

Used by weights and measure departments to check the accuracy of gas pumps.

Example........... https://www.collectorsweekly.com/stories/82646-rare-1-gal-gasoline-pump-testing-mea

 

Back in the days when I worked repairing gas pumps, they had to be government inspected and certified accurate before they went back to the service station. The examination used something similar to that. It was a tin that held a fixed amount of gasoline (5 gal. as I recall). At the top of the tin was a graduated glass tube. You filled it with 5 gallons from the pump, so it read exactly 5 gallons on the pump. You checked that against the reading on that graduated tube, and it had to be within a cubic inch to pass inspection.

 

WELL, THAT was FAST!!!!!

 

Dang, @Hollyblue , moreotherstuff, Ineedhelp, you guys are great!

I thought it had something to do with gasoline!

 

I definitely will, I saved my log in info...
thanks again

 

Welcome! Nice gizmo

 

Welcome, Nick!