17 APRIL 1926, page 8

The Optical Exhibition

I HAVE come away from the Exhibition arranged' by the Optical Convention at South Kensington (which closes to-day, Saturday . ) feeling that my eyes and the region behind them......

Ultra-violet Sunlight

I N Ancient Egypt there was the plague . of darkness which could be felt. In Modern England there is the plague of darkness which can he smelt, in our cities of dreadful day. In......