Rubber-soled shoes will skid on grass, but on most other surfaces they tend to develop too much friction.

ECONOMIST: Veterinary technology

Part of the reason, according to Miss Smith, is that on many surfaces rubber-soled shoes would be no use.

ECONOMIST: Veterinary technology

His only equipment, apart from rubber-soled boots, was a bag of chalk slung at the back of his belt, into which he dipped his hands to dry the sweat and improve his grip.

ECONOMIST: John Bachar, free-climber, died on July 5th, aged 52