I’ve come across a mystery. I recently acquired a manuscript map of France with a (from what I can discern) mountains comparative panel at the bottom. Unfortunately I do not read French so I have to make some guesses about it.
It is on very thin paper, possibly onionskin paper, mounted on a secondary thicker page. The lines on the map are fine and well executed. It appears that drainage basins are shaded in pastels (possibly political divisions–perhaps a reader with better knowledge of France can clarify, but because the shaded areas follow mountain ranges, I suspect they are watersheds). The bottom of the map features a comparative panel of mountains similar to an anonymous Portuguese map from 1824, the orological line, along with a hydrological line; the mountains are grouped by range in a valley sort. The cartouche bears “Em Jeanmaire & C 1853”, telling us an approximate production date (approximate because this is more of a “no earlier than” date).
The thin paper suggests that all or part of the map was a tracing of another map. Residual, faint lines are visible in the border, as well as overruns, further indicating this is a manuscript piece.
The orological line clearly shows the heights of mountains within the range. The line both takes the shape of peaks and the corresponding heights on in the adjacent data tables are consistent with mountains. The hydrological line is vexing. I suspect it is the heights of rivers, but my attempt at translating “parlage” turned up “chatter”, which, without understanding French, doesn’t make sense to me.
If you understand French, please fill in some of the gaps for me!
Most rivers comparatives look like stylized column graphs, where the rivers are scaled down and function as columns indicating length. Column graphs certainly lend themselves nicely to comparing lengths of rivers and at the time comparative views were popular, column graphs were still new, having been developed a few decades earlier by William Playfair. While just about any rivers comparative view resembles a column graph, the well executed among them are faithful, albeit smaller and straightened, facsimiles of the the rivers, providing more than just length, but also falls, lakes, deltas, tributaries, and adjacent cities.
Carey and Lea’s 1832 Chief Rivers does an excellent job of showing both rivers, but also the figurative and literal landscape through which they flow.
They show the Amazon (watch out for piranhas!) stretching from the Atlantic Ocean across the continent of South America, through the Andes, tracing the Beni River and showing Lake Titicica (the highest navigable body of water, by the way, at over 12,000 feet of elevation), and passing no fewer than five cities. From this image, we can tell that it supports a lot of people, with the cities serving as a proxy for population. Further, we can tell from the many tributaries that it drains a large basin, and from the mountains approximately 2/3 of the way inland from the ocean that it has alpine headwaters. Looking at the Mississippi, its delta and New Orleans–the Crescent City–are clear as day. The map shows two forts on the Mississippi, each indicated by a small cross, including Ft Mandan, where Louis and Clark spent the winter of 1804-1805. The presence of these forts and the several towns shown, with their histories in mind, tell us that this river was important in the European settlement of North America.
The detail Carey and Lea provided in the cases of the Mississippi and Amazon, as well as in the other rivers shown, makes clear that they are chief rivers in addition to simply being long rivers. Certainly being a long river is a compelling argument for it being important, however Carey and Lea show several very small rivers. The Thames and Forth rivers are tiny in the shadow of the Nile, Amazon, and Mississippi, but Carey and Lea provide context; showing London and Edinburgh provides the detail to understand that these are important rivers as they support capital cities despite being relatively short. After looking at the Mississippi and Amazon rivers, it is clear that their importance is not just in their length but also because of their ecology, the populations they support, and the commerce they facilitate. All of this insight would be lost if they were mere lines on a chart.
The rivers of the bible may bring to mind Noah hidden among bulrushes, but that’s not where they end. The Countries of Exile with Mountains and Rivers of the Bible by Hardesty, 1883, shows 11 biblical rivers in a small panel below another comparative panel of biblical mountains. This is the companion panel to the mountains piece that shares the same page.
As comparatives go, it’s unusual. Where comparatives typically (everywhere except perhaps this example) concern themselves with ‘principal’ features (I find that usually means largest, although that is up in the air with some comparatives), this comparative shows features described in the bible. Further making this view unique are the inconsistent scales used. A uniform scale is critical to a comparative in that without one, the ability to visually ascertain the relative size of a feature is lost.
To perform a scale analysis I measured lengths of the rivers as drawn and plotted that against their stated lengths, with each river shown as a dot. If the comparative had a uniform scale, the plotted points would fall on a line.
The scale plot generated in the analysis is not a flat line. Instead, it’s more of a curve, climbing steeply on the left hand side of the plot, then becoming shallower.
I split the longer rivers (Nile, Tigris, and Euphrates) which fell on the right hand ‘spur’ of the graph into a separate group and replotted them so that I could fit lines to each group individually. The result: within groups, the rivers scale consistently.
This finding points to the possibility that the author intended for this piece to be a visual tool for showing the lengths of the rivers, but for practical reasons could not do so in a way that would adequately address all 11 rivers. Quite simply, to show a 3,700 mile and a 19 mile river on the same chart would require either a chart so large as to be unwieldy or a chart that condenses the smaller features so much that it lacks resolution. The author no doubt wanted for the reader to see the differences in river lengths, but lacked (or chose not to devote) page space to show it, instead hoping that the reader would figure it out.
I am pleased to add Mitchell’s 1860 The World in Hemispheres with Other Projections to my collection. This is principally a globular projection but instead of the vignettes that would have adorned a 18th century map, additional views fill the corners: the upper left and right corners have comparatives of the rivers of the western and eastern hemispheres, respectively.
The use of comparatives in lieu of vignettes was common among 19th century maps, and we can infer from these that comparative views were perceived as worthy cartographic endeavors rather than mere curiosities. Page space was valuable, as evidenced by cartographers’ efficient usage of it, and easily could have been filled with other insets: select countries or cities, climate zones, or vegetation and animal life by region of the globe. Perhaps it was their role in commerce that made rivers an appealing feature to include; perhaps it was because many rivers were still being charted. What ever the reasons may be, they are beyond the scope of this analysis.
Instead, I’ll draw your attention to the orientation of the rivers. All western hemisphere rivers are depicted as emptying west to some sea off the left coast–the pacific ocean. Of course this is not accurate–although characteristic of comparatives, which took a vastly reductionist approach to compare the features by a single attribute–the Mississippi drains south into the Gulf of Mexico, the Amazon northeasterly into the Atlantic, the Potomac southeasterly into the Atlantic, and the Colorado south to the Sea of Cortez. The St Lawrence, subject of this analysis, flows east to the Atlantic.
Looking closely at the St Lawrence, the Great Lakes are in the reverse order; the eastern most lake, Lake Ontario, is shown as though it’s the western most, and vice versa for Lake Superior. While these are out of geographical order (geographical order is not expected in a comparative, generally speaking), this reordering keeps them in relative order vis-a-vis the mouth of the river. But the cartographers took this reordering a step further, not only did they flip the order of the lakes, they also flipped the shapes of the lakes, engraving their mirror images. Looking closely at Lake Michigan, it’s characteristic bean shape is shown curving in the opposite direction.
The decision to flip the lakes’ shapes offers some important clues into the Mitchell’s purpose. First off, reflecting the images around the vertical axis shows that he intended to make the image as truthful as possible. It signals to the reader that he did not make a mistake in showing the flow of the river–that a cartographer would flip the direction of the river and the orientation of the lakes–is hardly parsimonious. Moreover, the Great Lakes are perhaps the most important aspect of the St Lawrence for its economic and transportation functions. The river, thanks to some canals, and more recently a system of locks and canals, affords the outputs of the midwest industrial infrastructure, including that of Chicago, as well as western Pennsylvania and New York, cheap access to the Atlantic. To that end, the reflection of the lakes assists the reader in locating the major industrial hubs on the lakes: Chicago, Erie, Buffalo, etc. A quick flip of the image in Pixlr reveals that the lakes are mirrored correctly.
The quirky illustration of the Great Lakes underscores the ingenuity of 19th century cartographers, skill of engravers, and their efforts to make comparative views valuable and useful to their readers.
In previous posts I have discussed the scaling of waterfalls and Johnson’s scaling of mountains in his 5 panel comparative. This post revisits that comparative to examine the scaling of the rivers.
This is an innovative comparative in that it follows the Mountains and Rivers approach pioneered earlier in the century, but splits the features out by continent. This allows the reader to see the range in heights of the peaks within each continent. The same is true of the rivers aspect; the rivers are first grouped by continent, then sorted by length. Breaking the view into panels allows him to show more features and begets ready comparison within the continental grouping.
This approach carries with it a major hazard, however: the increase in resolution and organizational capabilities of this display, because it doesn’t maintain a constant scale across the panels, comes at the cost of distorted heights and lengths between continents. Where mapping is a discipline of tradeoffs, the impact of this is dependant on the purpose of this comparative.
We can envision several candidate reasons Johnson included this comparative in his atlas. The first, and most simple is to document the sizes of mountains and rivers around the world visually. The second, which piggybacks on the first, is to display the size statistics but to animate them with drawings. We can compound both of these objectives by considering whether he wanted to show the diversity within continents or across them.
In the case of the second reason, to show otherwise dry statistics in a more intuitive display, the distortion between panels is less important because the image is merely a scaffold to support the numerical height or length description. Whether he hoped the reader would compare within or across continents we’ll examine further down.
As to the first proposed reason, to visually display the heights/lengths, with the statistics playing second fiddle, the distortion is much more important, and distorted they are!
In Johnson’s comparative view the longest rivers of each continent (which I am terming “index” rivers) are all shown to be about the same length, within about 10% or so, while their stated lengths vary by as much as about 90%. When their differing scales are compared, the Volga, the smallest of the index rivers, is overstated by 70%.
If his motivation was to show variation within the rivers of each continent, this scale distortion is confusing but necessary as magnifying the shorter Volga makes it easier to perceive its size vis-a-vis the other European rivers. On the other hand, if his purpose was to show the differences in lengths across the continents, this is a disservice to his readers at best, if not downright dishonest.
But would he intend his readers to compare the rivers’ lengths across continents? Probably not. The first evidence for this is that each continent’s rivers are compartmentalized to distinct panels. The second piece of evidence to this end is the alternating sort direction: longest to shortest in the first panel, shortest to longest in the second, and so on. Because the rivers are stacked and alternating, the evaluation of the index rivers between panels is difficult, versus the side by side presentation of most mountains and rivers charts (which he’d previously published). Johnson without doubt knew this layout would make intercontinental comparison difficult and would not have chosen it had he wished for the reader to draw such comparisons. As for whether he sought to intentionally mislead the reader, it’s an intriguing proposition, and we may never know for sure, but we can easily dispute it as both not parsimonious and, as someone who relied on his reputation as a reliable authority on geography, playing with fire.
I am pleased to add two new comparatives to my collection: A Map of the Principal Rivers shewing their Courses, Countries, and Comparative Lengths by the Society for the Diffusion of Useful Knowledge (SDUK)
and Comparative Lengths of the Principal Rivers Throughout the World by Fielding Lucas,
of 1834 and 1823, respectively.
Lucas’ Comparative Lengths… is a very ‘conventional’ rivers comparative, where the rivers are shown sorted by continent, then by length, all draining into a representative body of water on the left. Of note is that the longest rivers of the Americas wrap, while the longest river of Africa is shown interrupted and truncated. What is to be gleaned from this? We can surmise that this is a matter of the author’s perception, right or wrong, that the rivers on this map of primary interest to the reader were those of the Americas, specifically the US. This map was clearly intended for a US audience and was published in Baltimore, MD. The treatment of the Congo & Niger as both interrupted and truncated tells the reader to be aware that there are long rivers in Africa, that the territory is unexplored, and that in the author’s mind they are of secondary importance.
In contrast to the above, the A Map of Principal Rivers … by SDUK is abstract and even surreal, even by the standards of comparative maps. It has an unusual sort, from my analysis it is sorted by the direction it drains, then by size. Interestingly, it shows all rivers emptying into a central water body. This might reflect an effort to highlight the interconnectedness of waterways. Further evidencing this is the inclusion of inland bodies of water, like Lake Michigan pictured with the St Lawrence, which are usually not shown on rivers comparative views. Alternatively, to focus on Lake Michigan, the inclusion of such a body might simply be a reflection of SDUK’s mission to provide the working class with scientific knowledge. Where Chicago was rapidly emerging as a center of industry in the early 1800s, it no doubt would have had a large working class who would have benefited from having a local point of reference. That said, SDUK was a British organization and their consideration of or distribution to American readers is unknown to me. Note that Lake Michigan is shown as straight rather than curved, as I’ve previously discussed (same engraver).
These lovely comparatives, one simple and one ornate, can tell us as much about their intended readers as they can about the understanding of the world at the time.