Links to external websites that feature content about the 19th century pair of transits.

http://www.skyandtelescope.com/observing/objects/daylightphenomena/3308756.html
All 147 glass negatives discovered in the vault of the Lick Observatory are digitally stitched together into a movie, which "shows Venus's silhouette flickering strangely as it marches across the Sun's face" in 1882.  From Anthony Misch and William Sheehan.

http://dlib.stanford.edu:6520/cgi-pbin/list_all_pdf.pl
Original publications scanned by Stanford University Libraries & Academic Information Resources and offered online, including:

• http://dlib.stanford.edu:6520/text1/dd-ill/transits-venus.pdf
  A Popular Account of Past and Coming Transits, by Richard Proctor; 1882 (30.7 MB)
• http://dlib.stanford.edu:6520/text1/dd-ill/transit-1874-1.pdf
  Account of observations of 1874 transit, edited by Sir George Airy; (35.5 MB).
• http://dlib.stanford.edu:6520/text1/dd-ill/transit-1874-2.pdf
  Accounts of expedition to Waimea, Hawaii, by R. Johnson; expedition to Kerguelen Island by Corbet and Coke; 1874; (34.6 MB).

http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1881otv..book....
1N&db_key=AST&page_ind=263&plate_select=NO&data_type=GIF&type=SCREEN_GIF
From the rare book collection of the U.S. Naval Observatory, this unpublished report details the results of each party in the American Transit of Venus Expeditions of 1874 and 1882.

http://home.europa.com/~telscope/ToV.1874.spectr.obs.doc
Spectroscopic observations of the 1874 transit of Venus in monochromatic light, from Peter Abrahams, considers reports that the sun was seen in monochromatic light before the 1874 transit, while two observers recorded Venus against the chromosphere during the 1874 transit.

http://www.bweaver.nom.sh/gill/gill.htm
"Six Months in Ascension: An Unscientific Account of a Scientific Expedition by Mrs. Gill;"  details six months on Ascension Island by Mrs. David Gill, printed 1878.  Recognizing the limits of the transit of Venus for calculating the solar parallax, David Gill set out to measure the parallax of Mars, which was nearing opposition, using a heliometer.  His wife Isobel accompanied him, and was vital in searching for and finding a more suitable site for observing than the original Georgetown, which was beset by poor weather.


Collection of photographic plates (dry collodion emulsion) of the 1882 transit of Venus; from the Naval Observatory and Transit of Venus Commission expedition.  North is up, east is left.

http://www.youtube.com/watch?v=8LkHm8jS1qg
Video of 1882 Transit of Venus re-animated from David Peck Todd's glass negatives; by Anthony Misch and William Sheehan.

http://www.library.uq.edu.au/fryer/hume/web/372.html
Photograph of "Transit of Venus Group, December 1882, Jimbour" from the University of Queensland.  (See images 372, 373, and 374.)

http://www.geh.org/ar/strip47/htmlsrc/lanternsld_sum00040.html
Multiple images on this page, such as "Transit of Venus Huts erected at Naval Observatory; transparency, collodion on glass."  From the George Eastman House Still Photograph Archive.

http://books.google.com/books?id=NQQZAAAAYAAJ&pg=PR1#v=onepage&q&f=false
Appleton's Journal of Literature, Science, and Art, Volume 12, 1874, pp. 170-174 discusses prior transits of Venus and challenges of observing in anticipation of the 1874 transit of Venus. 

http://tasphotos.blogspot.com/2006/10/us-transit-of-venus-expedition-1874.html
Tasmania in Photographs: The U.S. Transit of Venus Expedition 1874.

http://query.nytimes.com/mem/archive-free/pdf?res=F00E14FA355D1A7493C1A91788D85F418784F9
Original copy of Transit of Venus Lecture by Prof. C.A. Young, in Hoboken; from New York Times, 1875 March 3.

http://adsabs.harvard.edu/full/2004JAD....10....4M
A Movie of the 1882 Transit of Venus Assembled From Plates Taken at Lick Observatory by David P. Todd. By Anthony Misch and William Sheehan.

http://geo-mexico.com/?p=2493
Mexico’s international scientific expedition to observe the 1874 transit of Venus.