I'm making a few assumptions here based on the information you have given over the course of this thread. The first is that the birth certificate you have is for
Joseph Barns (as per FreeBMD), birth registered March quarter 1852
Lewes registration district.
He therefore could have been born in any of the following localities, all of which lie within the Lewes Registration district:
Alciston Barcombe Beddingham Berwick Bishopstone Chailey Chalvington Denton Ditchling East Blatchington East Chitlington Falmer Falmer Firle Glynde Hamsey Iford Kingston near Lewes Lewes Newhaven Newick Ovingdean Peacehaven Piddinghoe Piddinghoe Plumpton Ringmer Ripe Rodmell Rottingdean Seaford Selmeston South Heighton South Malling Southease Stanmer Streat Tarring Neville Telscombe West Firle Westmeston Wivelsfield
That's a lot of possible places where Joseph might actually have been born!
You also say that it gives his father's occupation as a sailor, mother's maiden name Downs.
There is a baptism as Ditchling on 28 March 1852 for a Joseph Barns, son of Samuel and Martha Barns. The father's occupation is travelling hawker. This is the only baptism for a child of Samuel & Martha Barn(e)s in Ditchling. By their very nature, travellers do not often stay in one place for very long so tracing their movements after this is not going to be easy.
I cannot find a Joseph Barnes (with the 'e') birth registration in the Lewes district in 1852, so I have to conclude the one I gave above is the same one that you found and for which you have the certificate.
I note also that you say the writing is not clear on it. I can't see how hawker could look like sailor, but I might be wrong.
There is a birth registered in the Rye Registration district for Daniel Barns, September quarter 1854, mother's maiden name Downs. There is a baptism for a Daniel Richard Barns at Udimore on 1st October 1854, parents Samuel and Martha Barns whose abode is listed as Brighton. Samuel is a chair mender.
So the 1861 census entry showing Samuel, gipsy labourer, aged 66 with a son Joseph aged 8 living in Portsea would be for the father and son shown in the 1852 Ditchling baptism.
Following up on the Walter Barnes in rosie's post (reply no 16 on Monday) whose mother's maiden name was shown as Downes, there is a baptism in Broadwater on 1 April 1860 for Walter Barnes, son of Samuel Barns, a traveller and
Sarah . Since that 1861 census entry for Mary, Elizabeth, William, Daniel, Kate & Walter is for Portsea Workhouse, there are no relationships to go on. This is getting more and more convoluted.
This sort of puzzle demonstrates how important every scrap of information might be when trying to sort out which lead might be the correct one - and which might be the one that leads you astray. You may have to track down every Samuel Barn(e)s and hope to find a Joseph or a Martha as well.
You still have not said when Joseph died. I don't suppose there is any chance that he survived until 1939?
Nell