Square Rounds, Finborough Theatre review - the science behind warfare, told in verse

The title of Tony Harrison's teacherly entertainment – it can't be called a play – refers to the square bullets invented by James Puckle to kill Muslims in the 18th century. This shocking morsel of information is provided by the brothers Hiram and Hudson Maxim, inventors respectively of the machine gun and smokeless gunpowder, who are two of the characters in Square Rounds.

That apparent oxymoron might also imply attempts to square impossible circles, to the irony of scientific curiosity so frequently leading simultaneously to beneficial and destructive ends. Hiram Maxim (played energetically by Letty Thomas) invented an inhaler for asthmatics as well as a mousetrap, a sprinkler system and various pumps and motors besides the gun which takes his name. Then there is the irony of the scientists determined to believe that their creative killing methods are for the ultimate good of mankind.

Square Rounds was first presented in 1992 on the Olivier stage as an informative extravaganza, all-singing, all-dancing, full of colour and magic, revelling in the resources of the National Theatre. The Finborough version, produced by Proud Haddock in association with Neil McPherson, is its first revival and is, of necessity, small-scale. The cast of 27 actors and musicians is replaced by only six, the razzamatazz mostly missing, but the essentials of the piece are there. There is even some simple magic – handkerchiefs change colour, candles disappear – and the young actors, all clearly having a ball, occasionally burst into song. More often they are handling rhythmic verse, gleefully pointing up insistent rhymes. The original cast was overwhelmingly female; now it is entirely so. 

The premise is that "munitionettes", stuffing canisters with TNT in the First World War, morph into historical figures to tell the story of their place in scientific warfare. The most significant of these, so horribly up-to-date from Syria to Salisbury, is Fritz Haber's chemical weapon, chlorine gas. It is extra resonant in the anniversary year of the end of the Great War: in a graphic moment the cast simply file across the stage, blindfolded, as in a Paul Nash painting. And, in a further irony, the gas will later be used by Hitler to kill Haber's fellow Jews. But Haber's other important invention was fertiliser, a beneficial use of chemicals which still helps to feed the world. Philippa Quinn plays him with the right mixture of sincerity and arrogance, and it is her scene with a passionate Gracie Goldman as Clara (pictured below, right), Haber's suicidal wife – herself a brilliant chemist – which comes nearest to true drama. Meaningful interaction between characters is otherwise rare. Clara sees that gas is not a more benign weapon than guns and would not shorten the suffering of the war, but having failed to persuade her husband, she shoots herself. 

The set has a toilet cubicle-cum-magic box at its centre. The proper ecological use of human waste is again a live topic, as it was in 1992 and 1850. Eva Feiler as Justus von Liebig (pictured above, left), founder of organic chemistry and proponent of nitrogen (available from excrement) in fertiliser, is fervent and funny, capturing the verse rhythm conversationally and matching it with a winning physicality.

Director Jimmy Walters, whose production of Harrison's earlier more exuberant piece, The Trackers of Oxyrhynchus, sold out here a couple of years ago, oversees some neat ensemble work. And Depi Gorgogianni, movement director, ensures some deft circling around the black-and-white cubes of Daisy Blower's flexible set.

The bones of several fascinating plays lie buried here, waiting to be clothed in Harrison's robust, rhythmic, refulgent language. But for all its quirkiness and ambition, Square Rounds remains a superior example of theatre-in-education, albeit here delivered in an intimate seminar room rather than a lecture hall.

• Square Rounds at Finborough Theatre until 29 September
• Read more theatre reviews on theartsdesk

@heathermneill