Regarding US Census records: I am looking for the "first" enumeration of the 1870 US Census for Philadephia, PA. The "second" enumeration is on
Sorry for the slow response! We had to do a bit of research on this one.
First of all, we looked at the list of 1870 census microfilm for Philadelphia at the National Archives, to know what we were looking for. It seems the first enumeration included the microfilms M593-1387 through 1414, and M593-1445.
We do have that full range on microfilm at the W. Dale Clark Library (3rd floor), and also the second enumeration (Reel 1415-1444). We have several microfilm readers, some that can scan to a flash drive or print, and they are available for anyone to use.
It does appear that Ancestry has at least some of the first enumeration; if you browse using the dropdown menus at the right (see image below) while in the 1870 census collection, the wards that are not labeled specifically "2nd enum." do appear to be first enumeration (I did not check all of them, just a couple. You can tell by matching the microfilm number, which Ancestry lists under "Source.")
FamilySearch.org also has the microfilms for both 1st and 2nd enumerations, but only the 2nd is available digitally on their website; the first would have to be ordered.
I hope this helps! Let us know if you have more questions!
Martha Grenzeback and Mark Sorensen, W. Dale Clark (Main) Library