'Professor Sparks & Thelmina' were one of the funniest British music hall acts for many years, reaching headline status in the 1930's with their novel comedy electrical act. They worked with the Crazy Gang before the 2nd world war at the London Palladium, and, during the course of  their stage career appeared at every music hall throughout the British Isles. Among their co-stars were Max Wall, Tommy Trinder & George Formby, none of whom would follow their act in the same bill.
Charlie Chester, in Roy Hudd's Cavalcade of Variety Acts, describes the act as follows:
"He would enter as a mad professor and switch on his machine, which generated electricity. He would then pick up two swords, put one on the machine and the other on his wife, Thelmina. She was holding, by a pair of tongs in each hand, a six inch nail. The audience would see the nail go white hot until she finally snapped it in two. He would give all sorts of demonstrations of how Thelmina, and their son, could conduct electricity.
The best bit of the act was audience participation. He would get a bunch of volunteers on stage to 'bath' the Electric Baby. The more they dipped the flannel into the water to wash the metal baby the more the electricity would be amplified. Their contortions were very funny. Nowadays he'd be locked up."

Off the stage, 'Professor Sparks' was the mild mannered George Rathbone, a native of Northwich, Cheshire. He studied electronics at Glasgow Technical College. At the age of 18 he had his own laboratory, and, by the time he was 30, had 25 patents to his credit. When he retired from the stage, at the age of 67 in 1959, he set up an electrical repair shop in Northwich. He died in 1972 at the grand old age of 80.
'Thelmina' was his wife Thelma Rathbone. She was obviously a very trusting & extraordinarily brave lady (see the video opposite), being electrocuted night after night for years on end.
She was born Thelma Crooks in Scotland in 1893 and died in 1974, two years after her husband.
Their son, George Rathbone (jnr.), who was an audience 'volunteer' in the act (he's the tall gentleman in the bowler hat in the 'Washing the Electric Baby' photo) died in 1977, aged 63.
All photos on this page are courtesy of magic historian Peter Lane.
Many thanks to Jon Marshall & Tim Cockerill from Magic Carpet Theatre.
Thanks also to Lyn McCulloch from the Family History Society of Cheshire.