Sir, - In the manufacturing of aeroplanes, tobacco smoke is often used to test the airtight seals of the cabin and cockpit for leaks.
I'm delighted to report that on the number 50 bus in Dublin, passengers have taken it upon themselves to perform similar tests on the ventilation and air circulation of the upper saloon. Some of these willing volunteers sit at the back and proceed to fill the bus with tobacco smoke, while the others move to the front. When the required level of smoke has been achieved, the passengers at the front give the OK with a frown and loud tuts. They then open the windows fully.
This responsible act of co-operation occurs each morning and evening without fail. - Yours, etc.,
KEITH BURKE, Selskar Rise, Skerries, Co Dublin.