Selling bets at Harringay Stadium, 1987

The Julius patent totalisator machine, an electromechanical machine of intriguing design, was installed at Harringay Stadium in 1930 and remained in use throughout virtually all the life of the stadium. Its purpose was to operate the tote. The tote is a form of betting which pits the bet of an individual against the collected bets of all others, and hence differs from fixed odds in which the individual bet is against the opinion of a bookmaker. Simple as the concept is, designing a method for operating a tote effectively within the constraints of the numbers attending a race course and the frequency of races is demanding.

See this movie clip and these photos also.

You can see some of this machine at the Museum of London.

Read more about the totalisor here.