7 APRIL 1939, Page 6

Incidentally a gift for overhearing considerably enlarged my knowledge of

the properties of the barrage balloons. They keep up, according to one young gentleman in the crowd, because they are filled with petrol. (Each balloon actually, I believe, costs the taxpayer Lao in hydrogen every time it is inflated—or deflated, as you may like to put it.) It was an older lady who added the information that they could do 30o miles an hour. jANUS.