2026-10-06 Welsh Newspapers Online (National Library of Wales), Parallax
URL: https://newspapers.library.wales/ (free, no login). A Cloudflare "Just a moment" check passed by itself after about 5 s; no CAPTCHA appeared.
Queries:
1. "Parallax" "zetetic", 1849-1885: 49 results, of which about 4 are relevant (many hits are other uses of "parallax").
2. "Parallax" "Bedford" level OR canal, 1849-1885: negative (the boolean was mis-parsed; hits on level crossings and Bedford Street).
Result: positive.
Articles read
- Denbighshire Free Press, 4 Feb 1882, p.6, "The Balloon Society of Great Britain" [web: https://newspapers.library.wales/view/3609549/3609555/55/] - "Dr. S. Birley", known as "Parallax", lectured on "Zetetic Astronomy" (with diagrams) to the Balloon Society at the Royal Aquarium, London, before a crowded audience. - The president, W. H. Le Fevre, C.E., said the Society was not pledged to the views. He reported that he had often observed from a balloon, at different altitudes, that the Earth's surface appeared neither flat nor convex but concave, and that the higher an aeronaut went, the greater the depression appeared. This is a first-hand aeronaut's statement printed in a newspaper, and it bears on claim 2 (the horizon from balloons). - The lecturer described "many experiments which he had made" and asked the audience to experiment for themselves. Discussants: Colonel Brine, Mr. West, Dr. De Lacy Evans, Mr. Robinson (British Museum), Mr. Robert Stephenson C.E. and Mr. Bidder C.E. - This shows Rowbotham still lecturing in 1882, under his medical name.
- The Cambrian (Swansea), 15 Apr 1870, p.5, "The Rotundity of the Earth" [web: https://newspapers.library.wales/view/3330809/3330814/29/] - Reprints Nature (7 Apr 1870), which quotes The Field. Six miles of the Bedford Level were used, with three signals each 13 ft 4 in above the water and 3 miles apart. Wallace predicted the central signal would appear about 5 ft above the line joining the other two. - The Field (the umpire's paper) says Hampden and Carpenter (Hampden's referee) assented to the method beforehand. Carpenter said he believed it had never been tried. But a treatise by "Parallax" in The Field's possession, with Carpenter's name written on its title page, describes a similar experiment in the same locality "with a result exactly the reverse". The Field calls Carpenter an "improper person" to be referee. - The telescope diagrams, acknowledged by both sides, are said to show the central signal more than 5 ft above the line. Hampden and Carpenter nevertheless claimed victory and threatened to sue the Editor of The Field. - Interested parties: The Field's editor was the umpire, and Hampden and Carpenter were parties. Both characterizations are reported. Check [calc]: the mid-chord bulge for a 6-mile chord on R = 3959 mi is 6.0 ft, or 5.2 ft with standard refraction (k = 0.13). This agrees with Wallace's prediction of about 5 ft.
- Monmouthshire Merlin, 3 Dec 1864, p.8, "Pickings from Punch" (snippet only): a Punch item mocking a birth notice for a daughter of "Parallax", read as an advertisement for the zetetic works. Shows public notice of "Parallax" in 1864.
Lead
The "little treatise, published by Parallax" with an experiment of reverse result is probably the 1849 or 1851 pamphlet. It is the inventor's own earlier account of a marker or signal test on the canal. Identify it and compare (priority 1).