And another Non motoring what is it

[Mike Hodgson]

Ok it's a safety lamp but at one time during the history of the last century it had specific purpose.What was it ??

[Keith Bennett]

If it's an oil-burner, that blue glass would show a green light so I guess it's railway related? (The old semaphore signals used oil-burners and the arms' colours were red and blue.)

[austina40sam]

Was it used during times when we had smog problems?

[Mike Hodgson]

If it's an oil-burner, that blue glass would show a green light so I guess it's railway related? (The old semaphore signals used oil-burners and the arms' colours were red and blue.)

Not railway Keith ,it is meant to show blue

Clue --Civil Defence

[Mike Hodgson]

Was it used during times when we had smog problems?

No, but it would have been used outdoors

[Keith Bennett]

Police use for - say - directing traffic at night/

[Mike Hodgson]

Police use for - say - directing traffic at night/

Not for directing traffic .
They were used as a warning light for -----???

Another clue WW2
Answer this evening

[austina40sam]

Was it used Mike to help people see where public air raid shelters were?

[Mike Hodgson]

Was it used Mike to help people see where public air raid shelters were?

No Sam
Look back at original post (safety lamp) same as used in mining

[monty]

some form of gas detection with a colour change warning of gas