The Carl Smith Collection
... is a very useful tool to help researcher identify basic data and sources of information on individuals, organizations, buildings, roads, land matters and important events relating to Hong Kong, Macau and China's coastal cities from the mid 19th century onward.
The Public Records Office allows the collection to be searched online at: https://search.grs.gov.hk/en/searchcarladv.xhtml?rpp=10
Previously the content of the cards could only be viewed at the Public Records Office, but as of December 2018 the search results now include scanned copies of the cards.
Thanks to Vannesaf for these good tips on how to narrow searches:
In case this isn't already known to most already, if you want to search a particular person, say Peter Hendrickson, I find that if you just type in Peter Hendrickson, it will search anything "Peter" and anything "Hendrickson", which may returns thousands of results.
What you must do is put into the KEYWORD search field:
Peter AND Hendrickson
Has to be CAPITAL "AND", not lowercase "and"
And make sure there is exactly only one blank space between Peter and AND, and between AND and Hendrickson
I also noticed that inputting that into the "names" search field will give much more unfiltered results than using the "keyword" search field using the "AND" term.