## vachaspati on atomic coordinates

The great brAhmaNa vAchaspati mishra, who was described as “sarva

tantra svatantra” provides a model that is equivalent to the 3D

cartesian system in his work nyAya vartika tAtparya TIkA (4.2.25) to

describe molecular/atomic contacs. The 3 axes were termed

pUrva-pashchima, uttara-dakShiNa and urdhva-adhara. The position of

any point is given by measuring the the distance along these

direction. The position of contacts between atoms can then be given as

numerical series of these coordinates.

ekatve.api dishaH Adityodayadesha pratyAsanadesha saMyukto yaH sa

itarasmAd viprakR^iShTa pradesha saMyogAt paramANoH purva

evamAdityAsta mayadesha pratyAsanadesha saMyukto yaH sa itarasmAd

viprakR^iShTa desha saMyogAt paramANoH pashchimaH tau cha

pUrvapashschimau paramANU apekSya yaH sUryOdayAstamayadesha

viprakR^iShTa desha sa madhyavatIM

evam etayoryau tiryagdesha saMbandhinau madhyasya Arjavena

vyavasthitau pArshvavartinau tau dakShiNottarau paramANU

evaM madhyandina vartisUryasanikarSha viprakarShau apekSha

uparyadhobhAvo draShTavyaH

samyukta saMyogAlpatva bhUyastave cha sanikarSha viprakarShau

pUrvasamkhyAvacchinntvaM va alpatvaM parasamkhyAvacchinnatvaM ca

bhUyastvaM