The subscribing websites (whose purposes are generally unrelated to the book digitization project) present these images for humans to decipher as CAPTCHA words, as part of their normal validation procedures.
In 1904 a commercial service was established to transmit nightly news summaries to subscribing ships, which could incorporate them into their on-board newspapers.
Although the station does not officially start broadcasting until 10pm, its crude attempts to tantalise its audience into subscribing starts earlier in the evening.