The program loaded first time, auto-ran, and used oolour, sound and graphics effectively. Each program was user friendly (of len with a touch of humour) and was well error trapped.

I did discover one bug - in the Compound program, when the computer gives the correct answer, it prints with the Over command on. As it prints across previous text, the correct answer seemed to be in Chinese!

I corrected this by adding line 3000 over 0, and after this the program worked correctly - check on this please, Alchemy!

Designed to cover the more complex chemistry topics up to and including O level, the programs are:

Formula... which will tell you the formula of a compound you enter. Atom... to calculate the number of moles from the given mass of an element or vice-versa. Molecule... to calculate the number of moles from a given mass of compound. Mass... works out masses in an equation. Volume... works out masses and/or volumes in equations.

A first-class presentation of these topics, useful for use both at home or at school, with a well-written accompanying text. A ZX81 version is available.

R.E.