I also discovered the absence of Joseph but history docs tells us that persons not on census were either in an institution, on shipping records' or at a different address.
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Everybody was included in the censuses, those in institutions, in the coastal shipping trade, and at whatever address they were at. If individuals were working that night, or were travelling, they would be enumerated in the house to which they would normally return on the morning after they had finished their shift, or where they were to stay at the next stop on their journey.
The purpose of the censuses was to enumerate everyone in the country alive at mid-night on the day of the census, wherever they were, and all Institutions like Workhouses, Prisons, Hospitals, Lunatic Asylums, where people were inmates were included.
Stan