Hi Tatty5.
Just a thought - you may have already looked into this, but I was wondering - if you could manage to get hold of the census sheet for that street in 1871, this may tell you the names of the people living at number 36 in 1871. Its possible that your orphan was sent to them after her parents died.
Its a bit of a long shot as the people living there in 1871 may not be the same people living there is '75, but I guess if the names are familiar to you (eg an Uncle or Grandparent), it would probably be a safe bet.
Only thing is, that I haven't actually seen any Scottish census forms (I am getting my Scottish census info from a site which just shows the transcript, not the actual form), I know with the English Census forms, that they show details of the whole street (or as much of one that can fit on one form). Not sure if the Scottish census forms are the same.
I think you can get the actual Scottish Census details from ScotlandsPeople for a fee.
If you want, I can give you the details of my ancestors which lived at 35. This should allow you to look up the street form, and you can go from there.
Regards
JKH