In short, she took the first step towards Radicalism, and entered on the road of rebellion against the Existing and Acknowledged.
During the governess era which followed this scene Isobel travelled far and fast along that road.

The lady, or rather the ladies, hired by her father, for his wife was allowed no voice in their selection, were of the other known as "determined"; disciplinarians of the first water.
For one reason or another they did not stay.

Isobel, though a quick and able child, very fond of reading moreover, proved unamenable under discipline as understood by those formidable females, and owing to her possession of a curious tenacity of purpose, ended by wearing them down.

Also they did not care for the atmosphere of the house, which was depressing.
One of them once tried to strike Isobel.

This was when she was nearly thirteen.