a minute later , lord ponsonby declared importantly , `` i agree with horace , who said , 'ambition is so powerful a passion in the human breast that however high we reach we are never satisfied- ' `` utterly unnerved by his unswerving gaze and unaware that lady camden had turned fully around and was listening to lord ponsonby with a mixture of disbelief , fascination , and ill-concealed mirth , alexandra shakily stammered `` m-machiavelli . ''