Answers on line

'Science Line' attempts to answer questions about science by phone (UK 0345 600 444). They enlist experts to help provide the answers. Between 2 and 5 % of the questions received relate to crystallography. For example: "Salt is made of crystals and so is diamond, why are diamonds much harder than salt?" Past questions and answers are stored in the WWW at http://www.campus. bt.com/CampusWorld/pub/Science Net/.