Vaisesika Sūtra 5.2.14

हस्तकर्मणा मनसः कर्म व्याख्यातम् ॥१४॥

hastakarmaṇā manasaḥ karma vyākhyātam ॥14॥

[हस्त-कर्मणा (hasta-karmaṇā) - by movement of hand; मनसः-कर्म (manasaḥ-karma) - movement of the mind; व्याख्यातम् (vyākhyātam) - has been explained;]

Through the movement of the hand, the movement of the mind can be deciphered.