Hello Again,
If you are really that keen on trying to find the burial of James Slack, I wander if you have tried a website called Deceased Online at all?
https://www.deceasedonline.com/I could not find a burial for my 3x Great Grandad, Henry Ringrose on FindMyPast, Family Search, or anywhere else. And the only place that I found it was on the above website.
He was buried in 1917, in Nottingham, most probably in an unmarked grave: There were other people buried in the same plot.
Regarding the 1841 Census, where I found a James Slack aged 18, in the same household as an Abraham Slack: Curiosity got the better of me, and I decided to look at the original Census image on Find My Past:
Both Abraham, and James on that Census were printers. Abraham was down as a: "Calico Printer". James was down as aged 18, and listed as a: "Silk Printer". What is interesting that the address of the street is put down as: "Bank Edge." But even more interesting is that at the top of this original image it states: "Township of Wildboarclough."
The transcription (not original image) on Find My Past just states: "Bank Edge, Prestbury, Macclesfield, Cheshire."
Here is a link to this original 1841 Census image on Find My Past:
https://search.findmypast.co.uk/record?id=gbc%2f1841%2f0107%2f0291&parentid=gbc%2f1841%2f0008416245What is interesting is that in the 1851 Census, your James was still a: "Silk Printer.":
https://www.familysearch.org/ark:/61903/1:1:SGVV-YJVI have already posted a link that I found showing Abraham Slack a: "Calico Printer" in the 1851 Census.
What I am getting at here is that I would be very surprised if this Abraham, and James, were not Brothers, or at the very least Cousins.
But I was thinking that there may be an "in between" scenario:
This is just a THEORY A POSSIBILITY: But it goes like this:
This James could have been born illegitimate.
Going back to my 3x Great Grandad Henry Ringrose: He was baptised Henry Pride Ringrose in 1837, in Hoveringham, Nottinghamshire. The name of his Mother was Charlotte Ringrose, and she was not married when Henry was born. The Father's name was not put down on the register, or the baptism record. But on the 1841 Census in Hoveringham, there was a William Pride, who was single, and living a few doors down from the Ringrose's. His occupation was a: "Framework Knitter", and he was living with his mother.
Anyway, to cut a very long story short, there were no other "Pride candidates" in the immediate area who could have been the Father of my Henry.
Henry married in 1860, in Nottingham. He lied on his marriage certificate. Under, name , and occupation of father he had written: "William Ringrose, Deceased.":
It is my opinion that Henry used the Christian name of his biological father, and the surname of his mother.
Henry's mother, Charlotte Ringrose, married Joseph Hall, in Shepshed, Leicestershire, in 1844. He was a: "Framework Knitter."
Henry married again in the 1880's, after his first Wife died.
This time on the marriage certificate, for name, and occupation of Father he had written:
"Joseph Ringrose, Circular hand."
So there may be a POSSIBILITY, that your James Slack, could have been baptised under a different name, and may have lied about the name of his Father, on the marriage certificate.
Therefore it could POSSIBLY be the case that Abraham Slack, and James may have been half brothers.
The above is a theory and something to think about regarding James.

Thank you very much.
