Suppose that a glass rod is rubbed with silk. Then the glass rod gets positively charged and the silk gets negatively charged. After this, the negatively charged silk is made to touch a pith ball. What kind of charge is acquired by the pith ball?
Because silk is not a very good conductor, the charge Will not flow. But if it did, the ball would get the negative charge since some of the negative charge would flow to it, reducing the magnitude of negative charge of the silk.