OHIOLINK hat put 500+ PDFs of brittle books in its catalog (search electronic AND acme).

Example:
http://rave.ohiolink.edu/ebooks/dmc/OSU/CollectorsGuideToHistoricalDocuments%5FScott%5F562pgs.070.51908301.pdf

Author Scott, Henry T. (Henry Thomas)
Title A Guide to the collector of historical documents, literary manuscripts, and autograph letters, etc. [electronic resource] : with an index of valuable books of reference, where several thousand facsimiles of handwriting may be found for the verification of mss. and autograph letters ; also a new edition of Wright's Court-hand restored ; with an introductory chapter for the use of students and facsimiles of watermarks / by Scott and Samuel Davey
Publish info London : S.J. Davey, 1891
Descript'n xvi, 218 p., 153 p. of plates : front. facsim
Note Assisted by Samuel John Davey
Appendices: Facsimiles of royal personages -- English celebrities -- Wright's Court-hand restored (plates only) -- Facsimiles of watermarks from the collection formed by the late R. Lemon