'AIRPLANE CLOUDS' SEEN OVER BOSTON

Boston received a foretaste of aerial warfare yesterday when two "airplane clouds" caused by army plane manoeuvres were reported by the Blue Hill Observatory. The clouds appeared as long thin streaks in the sky lasting for about half an hour.

They are caused by high speed planes flying at 15,000 feet. Moisture forms from the plane's exhaust and also from the friction with the air. A fleet of planes would make a blanket of clouds of considerable substance, while individual planes form wisps which grow in size as they drift.

Yesterday's manoeuvres held near Worcester made clouds of about 200 feet in length which had grown to three miles by the time they had drifted to Boston.

Such formations have never been seen near Boston. Their official name is cirrus although now they are generally called airplane clouds.