Computers: World of knowledge at the click of a button: Christopher Gilbert finds the beef in two of the leading encyclopaedias available on CD

Certain ingredients are enhanced when combined - gin and tonic, strawberries and cream, beef and Yorkshire pudding. But for the perfect mix, nothing can beat the heady brew of encyclopaedia and CD-rom. Vast, cumbersome volumes are transferred to one neat CD disk, opening up a magical world of information, sights, sounds, video and animation. All at the click of a mouse button.

Two of the heavyweights in the division are Microsoft's Encarta - based on Funk and Wagnalls New Encyclopaedia - and Grolier. In both cases, installation of the 1994 editions is straightforward.

However, when under the spotlights the differences become immediately apparent. Encarta's opening sequence is both exciting and informative - Yitzhak Rabin's historic words on the White House lawn last September: 'We who have fought against you, the Palestinians, we say to you today in a loud and clear voice: 'Enough of blood and tears. Enough'.' Grolier, by contrast, displays a lacklustre soundless gallery of people and events.

Even when battle is commenced, Encarta wins most of the rounds on points. It is more pleasing on the eye, easier to use and was clearly devised with the computer in mind. Although Grolier has a perfectly workmanlike feature menu, it lacks the overall style of its rival.

Nothing illustrates this better than their respective 'timelines': Encarta presents an imaginative and colourful spectacle, allowing the user to browse across the screen and through the centuries, stopping off at a particularly enticing visual item or snippet of information - cats were first domesticated by the Egyptians in 2500BC; ice cream was invented in China in 2000BC: it 'consisted of a soft milk and rice concoction packed in snow or frozen on a platter' and became a favourite dish of the emperors. All Grolier can muster is a long list.

Encarta is also decibels ahead in its use of sound - examples of musical styles around the world, samples of every language, historical audio; Grolier probably just shades it on video and animation with memorable Hindenburg airship disaster footage, a 'buzz bomb' being shot down over London in 1944 and authoritative scientific simulations. The spoils are shared on the maps front; and Encarta snaps up the pictures category.

But the real test of any encyclopaedia is the quality and depth of information. I put the rivals through their paces by examining recent school projects set for a friend's daughters - the Tudors and Ancient Egypt - topics of interest in the week's news, a likely holiday destination and those niggling little questions of daily life.

Bearing in mind the US origins of both, they emerge rather well from their British historical examination, though Encarta provides a greater overall range. Ancient Egypt goes to Grolier for similar reasons, although Encarta scores well on the more arcane Timeline items - Hatshepsut became regent of Egypt in 1504BC and crowned herself pharaoh the next year 'dressed in full regalia, including false beard, traditionally worn only by a king'.

The plight of Bosnia and the horror of Rwanda have been prominently reported, but in the welter of day-to-day events, the background to such conflicts is often glossed over. Both products fare surprisingly well, with Encarta's cogent Bosnia analysis ending with the prophetic words: 'In June 1993, the Security Council passed a resolution to create 'safe areas' for Bosnian Muslims. It called for the deployment of up to 25,000 additional UN soldiers and gave them the mandate to use force to defend those areas. While the safe areas provided refuge for many driven from their homes, the international community recognized the general ineffectiveness of this resolution.'

Grolier adds historical perspective to the tribal rivalries which led to the past week's carnage in Rwanda. 'The Belgians sharpened class differences by reclassifying Tutsi with less than 10 cows as Hutu and imposing forced labour, supervised by the Tutsi, on the Hutu. Until the early 1950s, educational opportunities were available only to Tutsi.'

But Nelson Mandela gets short shrift. Grolier has a crack at it; Encarta's effort is a lamentable two paragraphs.

After last weekend's tragic events at the Imola race track in Italy, I was keen to read the encyclopaedias' verdicts on Ayrton Senna's life. Notwithstanding that Americans do not follow Grand Prix racing, I was shocked to discover that neither Grolier nor Encarta gives him a mention.

And if you are planning a trip to Provence, buy the travel guide.

Finally, I turned to trivia. A sheep tick recently latched on to one of our cats. Where did the noisome little critter come from and how is it removed? Grolier fails to score and neither tome offers any help on the question of disposal - but Encarta wins this category with a flourish by providing an appropriately gruesome picture.

The Eurovision Song Contest threw up a couple of posers: the origin of the Maltese language and the population of Reykjavik. Not surprisingly in this case, both came up with the answers: Arabic - it is the only Semitic language in the world to use the Latin alphabet; and 96,708.

There are, of course, other important considerations. The first is price. When Encarta was released, it cost about pounds 200. Like everything else in the computer business, the cost has fallen dramatically and direct-mail outlets are now offering it at just over pounds 80 (including VAT).

But Grolier is now more than twice as expensive as Encarta - unless you happen to buy a sound card or CD-Rom drive which includes the encylopaedia in the package deal of enticements.

Grolier also has another significant drawback: graphics cannot be copied into other Windows applications, so a child compiling a history project on a word processor would be unable to illustrate it. An astonishing omission. If you are still not convinced, the news that a British edition of Encarta will be released at the end of the year should tip the balance. That is not to say that Grolier should be given 'nul points'. Against a lesser opponent, it would have made a decent fist of it. But Microsoft sets exacting standards.

CD Encyclopaedias

To get the most from CD encyclopaedias on a PC-compatible system, you need a 486-processor machine running Windows 3.1 with a double-speed CD-rom drive, a screen capable of 256-colour display, a sound card and 8 megabytes of main memory (ram).

New Grolier: Software Toolworks; 0444 246333; pounds 175 (inc VAT).

Encarta 1994: Microsoft UK; 0734 270000; pounds 81 (inc VAT).