Sir, – Henry Counihan (December 8th) points out that many people may have become desensitised to the relative magnitude of the numbers million and billion. My father-in-law, a professional chemist, gave me a wonderful example about 32 years ago. A million seconds is about 11½ days. A billion seconds is – you've guessed it – about 32 years. – Yours, etc,
ARTHUR HENRY,
Dundrum, Dublin 16.