Civil Records(Births, Marriages, Deaths, Census)
Proprietary websites like Find My Past and Ancestry will require registration and payment via subscription or pay per view. Amongst a wide variety of records you can access civil registration records.
General Register Office - Searchable index of births and deaths since 1837. Access is free; you will need to register. Certificates can be ordered for payment. The birth index provides the maiden names of mothers from 1837.
The Cornwall Online Census Project site provides transcripts of Cornwalla censuses from 1841 to 1891. Access is free, registration is not required.
North Hill parish can be found on these pages, viz: 1841; 1851, 1861, 1871, 1881, 1891.