Sentence:  At first merely fidgety, and managed with the greatest delicacy by the English postilion, then ill-tempered and capricious, swerving from side to side, necessitating in self-defence the use of the whip-—“ But only gently and <WSD>light-handed</WSD>, .." 
Meaning of the word marked with <WSD> tags:  In a light-handed manner.