6.40 Bioloey Form and Function. 7.5 Biological Control. 7.30 The Quantum Wave Equation.

The Embassy World Professional Snooker Championship from the Crucible Theatre,
Sheffield DENNIS TAYLOR , ALEX HIGGINS , TERRY GRIFFITHS and JOHN SPENCER should all be involved in today's second-round matches, always supposing they have justified their seeding in the first round.
DAVID VINE introduces highlights of both the morning and afternoon sessions as the Championship moves into its second week. Commentators
TED LOWE , JACK KARNEHM
CL1VE EVERTON, VERA SELBY
2.15 Racing from Lingficld
Coverage of four of today's races.
2.30 The Wheelers Restaurant Stakes (Handicap. 6f)
3.0 The Esal Maiden Stakes (5f)
3.30 The Esal Bookmakers Oaks Trial Stakes (ljm)
Leading Oaks fancies clash in this valuable trial over the full distance of the Epsom Classic.
4.0 The Tender Heart Stakes (Handicap. 1½m)
Introduced by JULIAN WILSON Commentators
PETER O'SULLEVAN , JIMMY LINDLEY
Racing television presentation by DAVID KENNING

A programme on the elements of music in which Dr Dinah Barsham aims to help with the harmonisation of two linked phrases in three parts. She introduces the use of non-essential notes and deals with how to look for consecutive fifths and octaves.
A BBC/Open University production
(Rpt)

helps you plan your weekend by previewing daytime programmes of special interest from the Open University. This week there's a clip from Two Yorkshire Families showing the local historian at work piecing together the story of two West Riding families from letters, diaries, paintings and estate records. There's also a trip to Pompeii to study Roman Interior Decorations, well preserved by layers of ash after the eruption of Vesuvius in AD79, and a discussion of business attitudes to education in The National Interest.

A season of classic feature films The Great K & A Train Robbery starring Tom Mix
' King of the Cowboys '
Once the most popular Western star in the world, the energetic Tom Mix - at various times a range rider, a sheriff and a Texas Ranger-was an expert horseman and is in top daredevil form as detective Tom Gordon , assigned to solve a series of mysterious robberies on the K & A Railroad. Disguised as a bandit. Tom outwits the villains and wins the hand of the railroad chief's daughter.
Screenplay by JOHN STONE Directed by LEWIS SEILER
(First showing on British television) Films: page IS

Frame o/ the Day
DAVID vine introduces an important frame from today's play together with the latest results and news from the World Championship at the Crucible Theatre.

with subtitles for the hard-of-hearing, followed by Weather

A series of six programmes made by young people 4: Inside Out
' It's a vicious circle - you can't get a job-so you go from boredom to bother-you get into trouble - you wind up in borstal-and when you've got a record - there's no way you're gonna get a job.'
Crimes/cops/courts/beaks/borstal A particular view from a group of lads who have all been in trouble with the law.
Additional words and music by the groups STEEL PULSE and CLINT EASTWOOD AND GENERAL SAINT
Made with the help of the COMMUNITY PROGRAMME UNIT

from
Barnsdale Geoffrey Hamilton and Clay Jones plant chrysanthemums for cutting throughout the summer months and show how to raise perennial border plants cheaply from seed. There's lots to do in the vegetable plot and the fruit garden gets attention too.
Produced by JOHN KENYON BBC Birmingham
Gardening hints on Ceefax page 269

The China Card
America's relations with China are in crisis; President Reagan's decision to sell 60 million dollars of military equipment to the fiercely anti-Communist regime in Taiwan is denounced by Peking as a serious breach of sovereignty. This diplomatic chill has encouraged President Brezhnev to play his ' China Card' and to try to woo China back into the Russian camp. With the superpowers again battling for influence in Peking, Keith Kyle reports from Taiwan -nervous of an American sell-out-and from Washington - anxious to avoid a collapse in its accord with Peking.
Deputy editor PETER KENYATTA Editor PETER IBBOTSON

by RHYS ADRIAN
Is Richard the pub bore, or is he someone very intriguing? Arthur is a man of habit - four pints a night and home by 7.0, but tonight it's past 11.0 before he leaves the pub.
I Ian Richardson as Richard
Lee Montague as Arthur and Rosalie Crutchley as Beth
Sound JOHN HOWELL. Lighting PETER WINN Designer RAY CUSICK
Producer ROSEMARY HILL Director DESMOND DAVIS

The Embassy World Professional Snooker Championship from the Crucible Theatre. Sheffield.
DAVID VINE introduces highlights of this evening's session from the second round.

Further coverage and results