The Triangulation of Verplanck Colvin

Few fully understand what the Adirondack wilderness really is. It is a mystery even to those who have crossed and recrossed it by boats along it avenues, the lakes; and on foot through its vast and silent recesses…In this remote section, filed with the most rugged mountains, where unnamed waterfalls pour in snowy tresses from the dark overhanging cliffs…the adventurous trapper or explorer must carry upon his back his blankets and heavy stock of food. Yet, though the woodsman may pass his lifetime in some of the wilderness, it is still a mystery to him. 1

 Verplanck Colvin, Superintendent of the Adirondack Survey

 Colvin oval photo


Between 1872 and 1900, perhaps no man traversed the Adirondacks more than Verplanck Colvin.  Russell Carson said, “With limitless enthusiasm and boundless devotion, he was exploring, surveying, mapping, and sketching the mountains, valleys, lakes and streams of the region, and writing voluminous reports and papers about them.” 2  Through his sheer personal will, he succeeded in lobbying the state legislature to appropriate funds for the Adirondack Survey and appoint him to the task. His explorations led to the discovery of Lake Tear of the Clouds as the source of the Hudson River and the first accurate elevations for Mt. Marcy and dozens of other regional peaks.

To map and describe this wonderful region, correcting the errors of early surveyors, and thus furnish a most important contribution to the physical geography of the State, is of course the primary purpose of undertaking the survey. But Mr. Colvin’s elaborate and interesting reports have been largely instrumental in calling the attention of the public to the attractions of the Adirondack wilderness both for the sportsman and the general tourist, and to the importance of taking any measures that may be necessary to preserve it forever as a mammoth pleasure ground. 3

1880 Editorial in The Cultivator and Country Gentleman

Indeed, Verplanck Colvin’s speech at Lake Pleasant in 1868 is credited as the first public advocacy for the preservation of the region as a state park. His later correspondences and reports illustrated his argument:

The Adirondack wilderness contains springs which are the sources of our principal rivers, and the feeders of the canals. Each summer the water supply for these rivers and canals is lessened…The immediate cause has been the chopping and burning off of vast tracts of forest in the wilderness, which have hitherto sheltered from the sun’s heat and evaporation the deep and lingering snows, the brooks and rivulets, and the thick, soaking sphagnous moss which, in times knee-deep, half water and half plant, forms hanging lakes upon the mountain sides…It is impossible for those who have not visited this region to realize the abundance, luxuriance and depth which these peaty mosses – the true source of our rivers – attain under the shade of those dark northern evergreen forests…The remedy for this is an Adirondack park or timber preserve. 4

While Colvin’s impact on the creation of the Adirondack Park is his most lasting achievement, his development of new survey techniques and technology should not be overlooked. It his efforts to unravel the mystery of the forest through detailed mapping that I find fascinating.

Triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly. Colvin used this method to map the Adirondacks using a series of mountain top signal stations.

Colvin was not one to avoid harsh and arduous effort in his attempts to map the Adirondacks. Notably, he did not retire to his Albany office in the dead of winter but rather used the frozen lakes to his advantage.

Raq baseline old

In February 1877, he came to Raquette Lake, as described by The Colvin Crew based on his field notes,

to establish a horizontally measured sub-baseline that could be used to strengthen his primary triangulation network of the Adirondack Mountains. This necessitated finding two points on the shore of Raquette Lake that would allow for the longest possible distance measured. Additionally, both points had to be visible from West Mountain and Blue Mountain. Following standard procedure, Bolt 69 was set on the south shore of Raquette Lake at a location known as Otter Point. With the ice cleared of snow, vertical wood stakes were set into the ice to act as guides in keeping the tape straight.   The 1,000 feet long steel “ribbon” was then stretched northerly with metal “ice blocks” being used at the intermediate chaining points for a total distance of 14,571.95 feet. The northerly terminus of this line was marked with a copper plug set in a small rock located at the northeast end of Needle Island. 5 [approximated in the author drawn map shown below]

Raq baseline google earth

Observations from the end point of such baselines to the mountain top signal stations required Colvin to devise two tools that advanced the accuracy of his methods. The Stan Helio is a spinning pyramid of shiny tin plates that reflect sunlight, providing a bright flash that could be seen in the daytime from twenty-five to thirty miles away with the naked eye and even farther through a telescope.

stan helio

Being able to see the mountain top signal stations from wherever his surveying teams were working was one piece of the puzzle. The other is for the surveying teams to accurately know exactly where they were when they observed the nearest signal station.

Determining a location’s longitude and latitude whether by the arc of the sun in day or by stars at night requires that one know the precise time of observation. The accuracy of Colvin’s surveying depended on all of his field teams synchronizing their timepieces to Albany’s Dudley Observatory time.

Here my research took an interesting turn when I discovered that Colvin’s solution to time synchronization involved my family. In August 1876, Colvin established an observation station on Thacher Island on Blue Mountain Lake. It was from here that he first observed the use of a nighttime powder charge flash signal that would communicate the accurate time to surveyors far afield. As he described

A supply of powder for the signal station time-flash had been sent to the mountain, and at a little before 9 P.M. we took up our station on a point commanding in the day-time view of the distant peak, and prepared to compare our watches with the chronometer signal. As we counted the seconds a bright flash illuminated the darkness, showing the mountain-top fairly, as lit by distant lightning. We found our time accurate, and were now satisfied that this method of distributing the Observatory time to the parties would be an entire success if the atmospheric conditions were favorable. 6


I was intrigued to know why Colvin would have used Thacher Island, when a point along the shoreline would have served just as well and eliminated the effort of rowing boxes of equipment out to the island. I knew that Colvin was from Albany, but did he know the Thacher family? My early hopes of a connection seemed dashed by viewing Colvin’s Reconnaissance Map of Tallow or Blue Mountain Lake, which incorrectly spelled our name as Thatcher. A family friend would never commit such an error.

Thatcher on map

I delved deeper into the accuracy of the map and found that the spelling was an inaccurate correction made by the printer. In Colvin’s own handwritten field notebooks, he repeatedly spells the name correctly.

Thacher in Colvin notes

Triangulation uses math to discover what cannot be readily seen and measured by comparing different points in relation to a baseline. I wondered whether an analogous method of drawing connections between points in time in the lives of Verplanck Colvin and the Thachers might answer my question.

The history of Albany provided the first clues. Verplanck Colvin and John Boyd Thacher were both born in 1847. Colvin’s father Andrew J. Colvin was the State Senator from Albany in 1860-1861 (the same seat occupied by JBT twenty-three years later) at the same time that George Hornell Thacher was the Mayor of Albany; both were prominent Democrats. 7  So their fathers were clearly acquainted, but did the boys know each other? Hilary Johnson King, archivist of Albany Academy, discovered that both boys were classmates in a group of forty students for three years (1858-1861). 8

The Thachers began to explore the Adirondacks in 1862 and established their summer home on Blue Mountain Lake in 1867. Verplanck Colvin began his explorations of the region in 1865. We have no correspondence or other evidence that John Boyd Thacher and Colvin were more than acquaintances in their youth. Colvin does not make reference to the Thachers in describing his earliest camping trips to the region, and yet it is hard to believe he did not consult with the first family from Albany to establish a base in the region.

I found that JBT’s and Colvin’s lives repeatedly intersected throughout the years.

JBT and Colvin timeline2

All of these intersecting points prove that the two men knew each other, but were they friends? Only after JBT’s death do I find evidence that it would appear so.

In 1869, Colvin was the first to bring national attention to an area of scenic beauty and scientific value with his writing and hand-drawn illustrations in Harper’s Magazine 14

To those who desire to escape for a day from the oven-like city in summer; who wish to enjoy a scramble among the romantic cliffs, in shady woods, beside cool mountain brooks and waterfalls; to view spots sacred to legends of wild Revolutionary days, of Tory and Indian depredation, naming place, precipice, and mountain…

One might think that Colvin was once again writing about the Adirondacks here, but the quote continues…

to gather the fossil corals and shells… to visit and explore known caves… among the cliff ledges, the “Indian Ladder” region of the Helderbergs offers superior inducements.

Verplanck Colvin Escarpment Illustration

The Helderberg Escarpment lies about twenty miles to the west of Albany and a two hour drive in 1869 when Colvin used the site as his training ground. The cliffs and fields served as a laboratory where Colvin perfected the self-taught surveying techniques that he applied to the Adirondacks. 15

Beginning in 1903, John Boyd Thacher purchased 300 acres along this escarpment to preserve its invaluable fossil record and intrinsic scenic beauty. After his death, JBT’s wife, Emma Treadwell Thacher, donated the lands to create what today is known as John Boyd Thacher State Park. 16

We might easily assume that Colvin influenced JBT to preserve these lands. However, unlike my previous “triangulations”, no assumption is required here. Within the 1915 annual report of the American Scenic and Historic Preservation Society, a description of the 1914 Dedication Ceremony for the park lists Verplanck Colvin as one of eight dignitaries who enjoyed lunch with Mrs. Thacher at her Altamont estate prior to the ceremony. 17

This is notable for two reasons. None of the numerous daily newspaper articles describing the ceremony mention Colvin’s presence, and he did not speak at the ceremony itself. Having been unceremoniously and a bit scandalously fired from his state position in 1900 by Governor Teddy Roosevelt, Colvin faded into a life of obscurity, became depressed and lived in hermit-like seclusion in his home in Albany. 18

His respected place of inclusion in Mrs. Thacher’s plans for the dedication is, I believe, proof of a lifelong friendship with John Boyd Thacher and furthermore, evidence that Verplanck Colvin deserves credit as the father of two glorious state parks.


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