Archaeologists at the University of Taxila have utilized multispectral imaging to reveal a previously invisible layer of text on a 5th-century CE birch bark scroll. The hidden writing consists of a detailed mathematical commentary on the Sulba Sutras, focusing on the calculation of square roots using a recursive algorithm. This discovery suggests that advanced Vedic mathematics continued to be a core part of the curriculum in Gandhara well into the Buddhist era.
The study, featured in the journal Antiquity, demonstrates that the ink used for the commentary was a different chemical composition that had faded beyond human sight. The researchers believe this finding opens the door to re-examining thousands of 'blank' or heavily damaged manuscripts using spectral analysis to recover lost scientific heritage.