INPASS

INPASS stands for "Indian Patent Advanced Search System". It is the search mechanism for Intellectual Property India (i.e. the Office of the Controller General of Patents, Designs & Trade Marks.)

Accessible here: https://ipindiaservices.gov.in/PublicSearch/

Date-restricted searches yield number of pre-1920 results. For many of these results, the data has not been fully digitized.

Hypothesis: Because 01/01/1900 is a default date in their database, many incompletely described patents from throughout the decades turn up in searches which include this date.

To a large extent the database actually begins in 1912. (This is suggested also by external sources, e.g. Adams, 2012, p. 138.)

Results from searching INPASS don't yield clear hyperlinks.