Two kinds of charges
If the glass is rubbed with a silk cloth, it acquires positive charge while the silk cloth acquires an equal amount of negative charge.
If an ebonite rod is rubbed with fur, it becomes negatively charged, while the fur acquires equal amount of positive charge. This classification of positive and negative charges was termed by American scientist, Benjamin Franklin.
Thus, charging a rod by rubbing does not create electricity, but simply transfers or redistributes the charges in a material.