The Invisible Ray (1936)

Starring Boris Karloff, Bela Lugosi, Frances Drake, Frank Lawton, Violet Kemble Cooper
Directed by Lambert Hillyer
(actor & director credits courtesy IMDB.com)

An obsessed scientist discovers a powerful new element in Africa which makes his touch poisonous, and when it is taken from him and his wife falls for another man, he plots a deadly revenge. 

The third pairing of Karloff and Lugosi features Karloff in the showier part (which apparently originally was supposed to have gone to Lugosi), but the Hungarian actor gives a fine performance as the distinguished scientist Doctor Benet, although it's far from an ideal showcase.  Karloff is more memorable as Janos Rukh, whose weary movements and penetrating stare create a believable character whose brilliance has been overshadowed by those have scoffed at his theories.  The film rather closely parallels Universal's earlier effort, The Invisible Man, casting Karloff as another killer maddened by his greatest discovery, and like that film, features some breathtaking special effects.  Depictions of planets moving through a starfield captured by Rukh's astral projector are of greater quality than similar scenes from productions made decades later, and the visuals depicting a character's demise at film's end are utterly unforgettable.  Franz Waxman, who created one of horror's best film scores for Bride Of Frankenstein, also contributes effective cues for this movie's soundtrack, including both menacing themes for Karloff's attacks, as well as some lovely music for Frances Drake's leading lady.