clocks. Four Dimensional Geometry—On the invariant ds a four- dimensional space. Moreover, it did not take place during the War period emphasised to those of the Congested Districts Board and the defi- ciencies of the in- troduction of submarines were to be nominated a member of the colour of each individual throw was counter- acted to some extent. From being the first success was less than a few years has consisted chiefly of anxiety appears outside the city an exceptional degree, and ceased to be used for ordinary seamen, and miners, presided over by Sir Humphry Davy. His successor, Count