Where history comes vividly to life

Most people in London, natives and visitors alike, know about the Science Museum and the Natural History Museum, each attracting more than a million people a year, as well as about the museums at Greenwich, the Planetarium, and the London Zoo, which draw about half as many.

But scattered across the city are dozens of smaller museums and centres where visitors can find out about London's science and engineering, past and present.

Here is a more complete list worth pursuing. Each place mentioned provides its own delight and fascination. It is advisable to check opening times by phone before a visit.

Alexander Fleming Labor-atory Museum, St Mary's Hospital, Praed St W2 (071-725 6528). Mon-Thurs 10am-1pm. Entry fee.

See the cramped conditions in which a Nobel Prize can be won, where Fleming sat at his microscope and discovered penicillin.

Bethlem Royal Hospital Archives and Museum, The Bethlem Royal Hospital, Monks Orchard Rd, Beckenham, Kent (081-777 6611 ext 4307). Mon-Fri 9.30am-5.30pm. Free.

Straitjackets from old Bedlam are on show alongside paintings by Nijinsky, Richard Dadd and others.

British Dental Association Museum, 64 Wimpole St W1 (071-935 0875). Mon-Fri 10am-5pm. Free (phone beforehand).

The crudity is evident in the old instruments for pulling teeth, and in the ivory, bone or gold replacements.

British Optical Association Foundation Museum, The British College of Optom-etrists, 10 Knaresborough Place SW5 (071-373 7765). Mon-Fri 10am-4pm. Free, by appointment.

Bejewelled 18th-century quizzing glasses, spyglasses, and lorgnettes sit alongside a display tracing the history of spectacles.

Brunel's Engine House, Railway Avenue (Tunnel Rd) SE16 (081-318 2489). First Sun of each month, 12noon-4pm. Entry fee.

Here is the southern end of the world's first pedestrian underwater tunnel and a display explaining its history.

BT Museum - The Story of Telecommunications, 145 Queen Victoria St EC4 (071-248 7444). Mon-Fri 10am-5pm. Free.

Exhibits range from semaphores, telegraphs, telephones and radio, to intercontinental satellite communication.

Chelsea Physic Garden, 66 Royal Hospital Rd SW3 (071-352 5646). Apr-Oct, Wed and Sun only, 2pm-5pm. Entry fee.

The Society of Apothecaries maintains this entrancing 320-year-old garden for the study and cultivation of plants of medicinal value.

Darwin Museum, Down House, Luxted Rd, Downe, Kent (0689-859119) Wed-Sun and Bank hols, 1pm-5pm. Entry fee.

You can see the rooms in which Darwin lived and worked for 40 years, and wrote The Origin of Species.

Faraday Museum, Royal Institution, 21 Albemarle St W1 (071-409 2992). Mon-Fri 1pm-4pm. Entry fee.

Here is the simple laboratory where a barely schooled blacksmith's son became one of the world's greatest experimental scientists.

Florence Nightingale Museum, 2 Lambeth Palace Rd, SE1 (071-620 0374). Tue-Sun and Bank hols 10am-4pm. Entry fee.

The actual lamp the lady carried through the hospital wards at Scutari is here; plus accounts of her work to improve public health.

Freud Museum, 20 Maresfield Gardens, NW3 (071-435 2002/5167). Wed-Sun 12noon-5pm. Entry fee.

Freud came to this house from Vienna in 1939, but the couch was brought over with him, together with other Freudian memorabilia.

Horniman Free Museum, 100 London Rd, Forest Hill SE23 (081-699 1872). Weekdays 10.30-5.30, Sun 2pm-5.30pm. Free.

Substantial natural history collection and a sparkling aquarium.

Kew Bridge Steam Museum, Green Dragon Lane, Brentford (081-568 4757). Daily 11am-5pm; engines run only on Sat and Sun. Entry fee.

The world's biggest beam engine, four storeys high, is only one among old machines hissing and steaming here.

Kirkaldy Testing Museum, 99 Southwark St SE1 (Curator 0322 332195). By appoint-ment. Entry fee.

Machines for destructive testing of girders, chains, and blocks of concrete illustrate the high quality of Victorian engineering.

Livesey Museum, 682 Old Kent Rd SE15 (071-639 5604). Mon-Sat 10am-5pm. Free.

The exciting science displays, changed every few months, invite enthusiastic participation by children.

London Canal Museum, 12-13 New Wharf Rd N1 (071-713 0836). Tue-Sun 10am-4.30pm. Entry fee.

Learn about the Regent's Canal barges, the families who lived on them, the horses that towed them, and the goods they transported.

London Gas Museum, British Gas, Twelvetrees Crescent, E3 (071-987 2000, ext 3344). By appointment only, Mon-Fri 9.30am-4pm. Free.

You know of gas cooking and heating and even of gas lighting. But a gas-powered radio? Discover the complete story of gas technology.

Old Operating Theatre, Museum & Herb Garret, 9 St Thomas St SE1 (071-955 4791). Tues-Sun 10am-4pm. Entry fee.

London's most gruesome museum. Be thankful modern surgery is unlike that shown and explained here.

Thames Barrier Visitors' Centre, Unity Way, Woolwich Rd SE18 (081-854 1373). Mon-Fri 10.30am-5pm; Sat-Sun 10.30am-5.30pm. Entry fee.

The Thames Barrier is a marvel of modern engineering. For the maximum awe-inspiring effect, approach it by boat from Greenwich.

The Vintage Wireless Museum, 23 Rosendale Rd SE1 (081-670-3667). Open nearly any time before 10pm. Free (phone for directions).

What happened to old valves and the wireless sets in which they sat? They ended up here, cared for with affection.

Wellcome Centre for Medical Science, 183 Euston Rd, NW1 (071-611 8888). Mon-Fri 9.45am-5pm; Sat 9.45am-1pm. Free.

The Science for Life exhibition is one of the country's best displays of modern biological and medical science. Superb information centre.

Wimbledon Windmill Museum, Windmill Rd, Wimbledon Common SW19 (081-947 2825). Open to the public Sat, Sun and public holidays, April to October, 2pm-5pm. Entry fee.

One of the few windmills in London houses an absorbing account of the history and technology of wind power.

A Guide to London Science by Dennis & Sylvia Rosen is published by Prion on 30 June.

(Photographs omitted)