​The 1956 reworking by Priyadaranjan Ray of Prafulla Chandra Rây's 1902 volumes is an interesting "moment" in the history of Indian science in the immediate post-colonial period.  It is not a reprint of Rây's original books, but a re-framing.  It was published by the Indian Chemical Society, and valorizes the idea that rasaśāstra was proto-chemistry.  As such, it plays down, and almost completely omits, the tāntrika materials to which PC Rây gave balanced weight. 

Further, Rây's own History of Hindu Chemistry evolved a lot between the first and the second editions.  After the first edition, Rây discovered a manuscript in the Raghunatha Temple collection that he felt was centrally important, and his second edition places that newly-discovered work at the centre of his account of alchemical history in India.  Rây explicitly modelled his volumes on the works of Marcellin Berthelot, whom he corresponded with (and met, if I remember correctly). So he had a genuinely historical interest in alchemy-as-it-was, which I think Priyadaranjan Ray did not. 

Best,
Dominik