H.g. Wells 
The Chronic Argonauts [EPUB ebook] 

There is absolutely no deception, sir, said Nebogipfel with the slightest trace of mockery in his voice. ‘I lay no claim to work in matters spiritual. It is a bona fide mechanical contrivance, a thing emphatically of this sordid world. Excuse me – just one minute.’ He rose from his knees, stepped upon the mahogany platform, took a curiously curved lever in his hand and pulled it over. Cook rubbed his eyes. There certainly was no deception. The doctor and the machine had vanished.