The inventor J. J. Royal developed a handful of patents in the late 19th Century and there are three known Doulton versions of these. 

  
Perhaps the most commonly known is the self pouring teapot, which pours tea when the lid is lifted. 

  
Page from a 1894 catalogue illustrating the toilet aquarius. 

The next is the toilet aquarius which featured a water vessel with lip on a metal stand that would pour water into the basin. 

The final example is a self pouring jug (not illustrated), along the same lines as the tea pots above.