HALF .the history of England, and no inconsiderable proportion of the sights of London, are bound up with the many courts and cells and stairways of the Tower, that gloomy fortresspalaee-prison that saw so many strange happenings between its foundation by the Romans and the time of Colonel Blood's audacious attempt on the Crown jewels. Mr. Allen Walker , the well-known lecturer and authority on old London, has indeed chosen a fascinating subject for the first of his talks on the great,buildings of London. This afternoon he will deal with the Tower as a fortress and a palace, in the earlier part of its history.