It was only at night, indeed, that she felt secure enough from surprise to concentrate her mind to the utmost.
Perhaps the unwomanly nature of the science made her instinctively wish to conceal her love of it.

But the more profound reason was that in her mind mathematics were directly opposed to literature.

She would not have cared to confess how infinitely she preferred the exactitude, the star-like impersonality, of figures to the confusion, agitation, and vagueness of the finest prose.

There was something a little unseemly in thus opposing the tradition of her family; something that made her feel wrong-headed, and thus more than ever disposed to shut her desires away from view and cherish them with extraordinary fondness.

Again and again she was thinking of some problem when she should have been thinking of her grandfather.