Electricity: a large electro-static generator machine in use in the Colosseum, London, with many condenser jars and four operators. Wood engraving, 1839.

The Colosseum was on the east side of Regents Park in London, between Cambridge Terrace to the south and Chester Terrace to the north. The Gallery of Natural Magic was an exhibition of popular science. "Braham and Yates … decided to seek the Colosseum's salvation … in the current rage for popularized science and technology—by converting the protean premises into a Marylebone version of the newly opened Polytechnic Institution not far away in Regent Street …. The Colosseum earned good marks from the press for the contribution its Gallery of Natural Magic made to the culture of the masses. There was a fair amount to see and marvel over, in addition to optical illusions and scary ventures into 'the World of Spirits,' the former marine cavern, where a performance entitled 'Phantoms of a Witches' Sabbath' was put on for children. Especially admirable were the achromatic solar microscope, magnifying (it was said) up to 4,665,600 times; a Gregorian reflecting telescope; and a 'plate machine' with 'electric surface of upwards of 80 square feet … so constructed as to give a striking distance or length of spark, hitherto unattainable.' But if the metropolis could support one hall of astounding magnifications and immense spark gaps, it could not, or would not, support two; and the Colosseum's show, unlike that at the Polytechnic, was a hastily conceived and slapdash enterprise. And so, in 1840, the summer variety bill was restored in what now was called the Royal Colosseum Theatre and Saloon of Mirrors." –Altick, loc. cit.