The 49th Parallel Boundary Survey - the logistics and the science
Monument 155 on Carson Road
If you're driving on Carson Road in Grand Forks, in the Carson or Almond Gardens area near what used to be the old Carson Bridge across the Kettle River, you can't miss the concrete pillar beside the road reminding you that in fact you're steps away from the International Boundary. You wouldn't expect to see a border wall here, nor even a fence, although there is one laying flat to the ground in the weeds. The remnants of this fence can be seen climbing the gentle slope eastward and beyond. A bit of online research reveals that this concrete obelisk, or at least a more primitive version of it, has been here on this very same spot since 1860 when it was merely a pile of stones designated as Monument No. 54. It was later upgraded and reassigned as Monument No. 155 by a later Boundary Commission and survey.
The supervision and well-being of these monuments or markers along our internatiomal boundary is being enforced by a 1924 joint treaty between our two sovereign nations and a two-person International Boundary Commission that has existed for this purpose to this day. And they seem to have been doing their job well, as Monument 155 appears to be in excellent condition. It was last visited for inspection by Commission officials in 2013-10-15. There are about a dozen other monuments along the boundary between Carson and Christina Lake, some are concrete, others are mostly bronze or stainless steel.
For a birds-eye view of all current boundary monuments between Lake Osoyoos and Waneta on the Columbia River, the so called "West Kootenay-Boundary Country", you can view a wide-angle aerial photo-composite posted here: (Link)
A few excellent historic topographic sheets of local interest (1901-1905), including monument markers, can also be viewed here: Similkameen, Osoyoos, Midway-Carson, Carson-Cascade, Waneta-Fort Shepherd.
About the historic Boundary Commission survey in the West Kootenay-Boundary (1859-60)
An excellent comprehensive historic account of the Pacific Northwest Boundary Commission survey appears in a collection of letters between Col. J.S. Hawkins R.E., and the British Colonial Office in London, the "Foreign Office Correspondence 1856-1871". The following is a brief summary of these letters dealing specifically with the historic survey of the West Kootenay-Boundary.
According to the Hawkins letters referenced above, Capt. Haig R.A., the chief astronomer with the British Royal Engineers, was the first member of the Boundary Commission survey team to visit the Grande Prairie (now Grand Forks) in 1859, at what was then called the second crossing of the Nehoialpitku (Kettle) River and the 49th parallel. He set up an astronomical observatory-tent there at Station Inshwointum on October 19th, near the current Carson obelisk, and having made the necessary observations and calculations of latitude at the station by the 28th of the same month, he continued with ground measurements to locate the first several boundary monuments westward and eastward along the boundary nearby. These earliest markers were typically loose-stone cairns, 6 feet square at their base and six to eight feet high, assembled by sappers under the supervision of the survey astronomer. The first of these at Carson, was designated as Monument No. 54 (108 in a later British Atlas), with other monuments located every mile or so eastward toward the next astronomical station previously planted by the Americans at Camp Statapoosten at the third crossing of the Nehoialpitku River near Cascade. Capt. Haig completed running the parallel to Statapoosten by December 10th, while in the meantime, instructing his assistant astronomer Lieut. S. Anderson, to continue and complete marking the boundary westward, back from Station Inshwointum to the first crossing near the current town of Midway.
Spending the winter of 1859/60 at the Boundary Commission barracks at Fort Colville, Capt. Haig and Lieut. Anderson then proceeded eastward next spring and the following year, to assist Capt. Darrah with the survey in progress to its eastern terminus at the crest of the Rockies. Captain Haig subsequently returned from there to the astronomical stations at the Columbia River (near Fort Shepherd) in 1861 to survey the last remaining stretch of the survey over the Paulson-Santa Rosa summit to Statapoosten at Cascade.
Photo ... view Capt. Haig and Capt. Harrah at work at the Yahk River astronomical station (ca. 1861).
Hawkins' letters also describe the earlier discovery of an unexplained irregularity in the survey between the Similkameen River and Statapoosten at Cascade. The matter was deemed especially urgent as it had rendered questionable all the recent border marker locations and forest cuttings across that whole segment of that boundary survey. There was a disparity of aproximately 800 feet between British calculations of latitude at Osoyoos and American calculations at Cascade. An accurate determination of latitude at Statapoosten would furthermore also affect Capt. Haig's pending survey eastward over the Paulson-Santa Rosa summit. It was eventually concluded that the methodology and results of both parties were not at fault and that the discrepancies were either due to magnetic influences affecting plumb lines or by an inconsistent selection of circumpolar stars used in their astronomical calculations. Nonetheless, a resolution was necessary and a special meeting of the minds was organized at Fort Colville between both Commissions where it was decided to adopt a "mean parallel". In other words, it appears that this segment of the 49th parallel was to be marked on the ground as an "arbitrary average". The American survey party which had previously been criticized for their lack of enthusiasm for cutting survey sight-lines, volunteered to do just that. They returned to the affected border to make additional astronomical calculations, to re-cut forest sight-lines and remove or replace problematic stone cairns. It is reassuring to note that subsequent official surveys made further determinations and adjustments to the border to confirm a "measured" official 49th Parallel.
You can view two pages extracted from the "Foreign Office Correspondence 1856-1871" volume (pgs 46-47) most relevant to this web page (Link) as well as a second extract (pgs 71-72) dealing with Capt. Haig's survey of the boundary line over the Paulson-Santa Rosa summit here: (Link)
The location of the Carson monument and other historic monuments in the Grand Prairie (Grand Forks Sunshine Valley) are labelled here on the Google Earth image at the top of this page, numbered in descending order between Mnt 54 (108) and Mnt 42 (120). If you are a Google Earth user, you can download and open this kmz file (Link) in your copy of Google Earth and see even a bigger picture ... all the historic monuments between the Similkameen River in the Okanogan and Fort Shepherd on the Columbia River.
These Google Map monument numbers and their geographic co-ordinates were gleaned from survey statistics and tables included in Marcus Baker's Boundary Commission 1900 Report to the U.S. government, incorporating Col. J.S. Hawkins R.E. survey tables from 1860-61 as seen below. You can also view this table (British sources only for simplicity) in its entirety here (Link).
49th Parallel survey science and logistics
Aside from monuments, the Google Earth kmz file includes the location of a number of historic Astronomical Survey Stations or Camps, some British, some U.S. ... such as the British Inchuintum Station at Carson and the U.S. Camp Statapoosten at Cascade. The astronomical stations were essentially field observation posts for tracking the transits of circumpolar stars across the local north-south meridian to determine local latitudes. The process was rather simple in its concept ... to determine the angle between a known star listed in an almanac (such as the pole star) at its zenith and the observer's horizon. You can roughly do it with a simple geometry set protractor. But a specialized astronomical instrument, the Zenith telescope was designed for this purpose enabling the accurate tracking of dozens of stars in a single night session. Even then several nights of observation were necessary to arrive at a precise determination of latitude. Once the station co-ordinates were determined, the actual locations of individual monuments (or beacons) marking the boundary, were determined by geodetic (ground based) measurement from the astronomical station ... including triangulation, using theodolites or even simple chain measurement.
An excellent detailed account of this process appeared in the appendix of an article by Chief Astronomer Samuel Anderson, in the Royal Geographical Society, Journal (London), 46 (1876). Although the report deals with the later prairie survey between the Lake of the Woods and the Rockies, Anderson employed the same instruments and methodology in the Northwest Boundary survey, when he was an "Assistant Astronomer". The appendix of this report can be viewed here: (Link)