but the book is from 1844... i think
heres the link to it anyways
The Sacraments: an inquiry into the ... - Google Books
I'm doing honours in ancient this year and finding heaps of my primary sources on google books (actually looking at 19th century stuff, so heaps from 1840s-50s). Some I just print out (its book with a staple!) and others i don't. I don't think it matters that you got it off google books, they photocopied it page for page, it's just as if you had it sitting in front of you (except it's a lot cheaper than going to London or the US!).
Of course, you can always just say google books, and give the url as others suggested if you're really worried.
edit: also the sacramentals has been republished, or at least you can buy copies of it (some of them will actually just be glorified photocopies of the original but bound like a book) check book depository uk etc (not that you actually want to buy the book, but you would be surprised how much is out there! I just bought three reprints of books from 1839/41/54- the glorified photocopy kind that looks like a book on the outside, and looks like a dodgy photocopy on the inside)!