Most Irish 1841 and 1851 census records were lost in the 1922 fire at the Four Courts in Dublin. Before the records were lost, though, extracts had been made from some of them to check the age of those applying for Old Age Pensions (from 1908 onwards). Forms entitled 'Extract from Census Return' have survived. They can now be searched and viewed free on FamilySearch (there are 32,472 images in the collection). The form asked for full name of applicant, address, full names of father and mother of applicant, details of where they would have been living at the time of the census and name of head of household if that was not the applicant's father. There are notes on search results. From the few examples I looked at, the amount of detail varies greatly: some just say 'not found', some confirm the applicant's age but don't give other information, and others have names & ages of other household members. Even if the search was unsuccessful, the forms might have crucial clues for genealogists, such as mother's maiden name. The search form is here: https:// familysearch.org/search/collection/2346275 For more about these and other related records, see here: http://www. irish-genealogy-toolkit.com/irish-pension-records.html
Interesting, I guess the applicant was often one of the children on behalf of parents who couldn't write. One doing so from Glamorgan in Sth Wales. 2 William Murphy's in Cork, wonder if one was my Jane's Dad, I never knew who her Mother was. Perhaps they had already left Ireland & moved to Liverpool or similar place.
The chance of finding a specific person is relatively slim: there are only 32,472 images in this set. That's only a small fraction of the number of pension applications and it's an even smaller fraction of the number of people who would have been on the census. I suppose most applicants had other documents to prove their age so a census search wasn't necessary. See the Irish Genealogy Toolkit link in my first post for more about the number of applications and a link to another site where you can search a different set of pension records. Though by definition the pension applicant had to be alive at the time of the application, not all the people in this particular FamilySearch database were, for parents' names are indexed. I am not sure if other household members' names are indexed, when those are given on the forms, nor do I know the total number of names in the database.
I prefer the search form layout on The Irish National Archives site which can be found at http://censussearchforms.nationalarchives.ie/search/cs/index.jsp You don't have to fill in all details,only the ones you know