SOMETHING IN THE AIR. By Jan Mark. Doubleday pound;10.99

The mists of time part for views of London across the centuries, writes Geraldine Brennan

The square mile of the City of London is full of doorways into the past for those who can open them. Julie Hearn has her eyes peeled and her ears tuned for the language of a more turbulent time in her richly textured first novel.

A handbill for Bartholomew Fair freak show in the early 18th century prompts the time-slip adventure tale of outcasts, prejudice and scientific advance on two sides of “the gap” into which Tom stumbles in his grandmother’s cellar.

In a house, “next to the Black Raven in West Smithfield”, Astra the “Changeling Child”, so frail that she’s transparent, is put on show by her cruel keeper. Her family are Gorilla Woman, Bendy Man and Giant. When Giant dies, Tom’s 21st-century technology saves him from the grave-robbers.

Three centuries later, Tom’s mother, being treated for breast cancer, takes on her own mother and the world in fury at her changing body being consigned to freakdom by others’ ignorance and embarrassment.

Tom has an only child’s responsibilities of mediator and mender in his emotionally laden home life and in the alleyways of 1717. Hearn’s evocative names and authentic oaths will attract Harry Potter fans, as will the sense of a strange and perilous world within arm’s reach.

But the only magic is man-made, and the outcome is all the more satisfying for being historically sound.

Jan Mark’s novel recreates another period of scientific advance, the 1920s, in which a grieving population turns away from religion but still needs something beyond the strictly rational, such as spiritualism or belief in fairies.

Peggy, daughter of a Great War widow, is a rationalist, and quicker than her dull teachers or priggish sister to welcome change. But she will benefit from such modern advances as the wireless and zip fastener later than most, and is stuck with buttonholing and dreams of a magic box that would bring music to her bedside. More distressing is the lack of explanation for the strange sounds in her head.

London represents independence as enjoyed by Peggy’s delightfully stroppy Aunt Stella, and contact with spiritualists, socialists and dangerous new ideas. It offers Peggy an alternative to stultifying school, where questioning the established order or knowing the facts of life is grounds for notoriety.

The glimpse of a past era of girls’ education should chill today’s readers, but is more likely to amuse. Through this likeable heroine they will absorb a timeless message: knowledge is power, and breakthroughs are more powerful when you have made them yourself.