I am not an expert but I like to collect vintage FP's. Only some people has 'the secret' of dating, so as a buyer I always need help. It would be very useful if the more experienced FPN members would render evident some wrong datings that happen to appear even in the case of the more honest sellers on eBay (and not only) This auction for a Wirt eyedropper seems to me curious. The barrel and the cap is of an early Paul E Wirt eyedropper, as for the feed, the vent-hole type was patented in April 1903. The two-line print was used by Wirt from 1889 until 1902. Could be such an ED considered from the 19th century as the seller afirms? I think that the feed is a later replacement, but the seller mentioned nothing