Comparing Lake Michigan

I was fortunate enough to add this charming, and made all the more so by its diminutive size at less than 4 x 6 inches, lakes comparative to my collection. It’s from Carey & Lea’s 1832 Family Cabinet Atlas and engraved by Hamm.

Principal Lakes of the Western Hemisphere by Carey & Lea, 1832.

While I was examining it I noticed that rather than being shown as is, looking like an elongated kidney bean, Lake Michigan is shown as straight as a board. Mind you this was engraved in 1832. I immediately pulled out 1851 Tallis comparative of western hemisphere features and saw that lake Michigan is shown in its true curved form.

Tallis 1851 comparative of Western Hemisphere features.

Why was this? What happened in the intervening years that begot this change? Were better survey techniques developed? Was the Carey & Lea comparative based on old data? If there was another survey, why, who commissioned it, and who financed it?

I did a little reading but didn’t find any satisfying answers. If you know, please tell me in the comments.

In case you’re wondering, my Tallis is from Barry Lawrence Ruderman’s gallery and my Carey & Lea from Rare Maps and Books.

© Peter Roehrich, 2015


A Lovely Waterfall Landscape

Comparative Waterfalls
A Comparative Picture of the Principal Waterfalls in the World by C. Smith & Son. (Rumsey) Shows waterfalls in the Eastern and Western Hemisphere. Gavarny is the tallest and the last of the Nile is the lowest. 1836.

This gorgeous comparative is representative of the illustrative, landscape style common in the the genre in the early 19th century (1836 in this case). Making it all the more stunning, it’s far larger than many comparatives, measuring over 1 foot by nearly 2 feet.

Although more of a “picture” than the graph-like format of later comparative views, it has all the characteristics of a comparative. The most simplistic of the criteria is that it has multiple of the same type of physical feature, repeated side by side for sake of comparison of a particular trait: waterfalls compared by height. Further, the waterfalls are grouped by hemisphere, but more or less are arranged in an overlaid valley sort. That the waterfalls are arranged by height rather than their geographic position (i.e.: east to west) is critical to a comparative as it allows easy determination of the relative rank of a subject as well as approximation of its size. The pastoral scene style of this comparative automatically conveys upon it the next characteristics–simplification and continuity between the subjects. Distinct images of features positioned adjacently on a page do not add up to a comparative. Moreover, the depictions of the features are to present a reductionist image as a detailed picture would competing with the comparative aspect. (I describe the characteristics of comparatives here, too.)

The final characteristic is one often not associated with a landscape: accuracy of scale. This image is scaled correctly, although it doesn’t look it at first glance. The surface of the waters into which the waterfalls flow is hidden for the waterfalls in the background (the taller ones!), causing it to appear as though the bottom of a waterfall in the back is the top of a waterfall in the foreground, making the scale ambiguous. Add to that the sense of depth of the image, causing the eye to interpret the rearmost waterfalls as appearing smaller due to perspective. However, if the waterfalls are measured from the base of the first one to their tops, they scale correctly.

Scale Analysis - Comparative Picture of the Principal Waterfalls
Analysis of the scaling of features on the Comparative Picture of the Principal Waterfalls of the World. (Own work)

To evaluate this, I performed a scale analysis. I downloaded a high resolution image from David Rumsey. After opening the image in GIMP, I measured the distance from the bottom of the first waterfall to its top, then repeated for several additional smaller waterfalls behind it, always starting my measure from the bottom of the foremost waterfall. I plotted the measurements against the stated heights of the waterfalls and found that they fell in virtually a perfect line–the comparative is scaled linearly. (Check out David Rumsey’s record for this map:

Taken together, between its beauty and accuracy, this is one of the most well executed of the early comparatives.

© Peter Roehrich 2015

Humboldt’s Map

Humboldt's 1805 map of plants encountered on Chimborazo in the Andes. (Buttimer)
Humboldt’s 1805 map of plants encountered on Chimborazo in the Andes. (Buttimer)

Humboldt, an early 19th century biologist (near and dear to my heart), is credited with sparking the discipline of comparative mapping. His map of the distribution of the flora on a South American mountain is handsome, and may have inspired the early comparative publishers, but it is not a comparative, rather it is a profile or elevation.

Whereas a map is, broadly speaking, a simplification of physical features to promote understanding, it no doubt qualifies as a map; it shows the distribution of plant life across the face of the mountain. Insofar as a comparative map is the rearrangement of physical features by some trait, usually size, to further promote understanding of geography, it is not a comparative.

This map is certainly an great example of early thematic mapping. Thematic mapping is the plotting of non-topographical features on a map and differs from general mapping which shows terrain, boundaries, etc. Moreover, it is an innovation in thematic mapping, being the first to my knowledge to apply thematic principles to a profile, plotting plant life as the occur on the mountain side.

The features on this map, a single mountain and the plants on it are arranged as they are actually encountered on the earth, violating the first criterion for comparative mapping; the features on a comparative map must be arranged so as to highlight the differences in a particular trait, usually size. On the other hand, this map hints at the importance of comparisons, and may well have encouraged subsequent development in the genre by showing the heights of other mountains in the margins. To be sure, the heights of other mountains are not shown pictorially, again violating a tenant of comparative mapping, but the idea is there.

Importantly, his map made waves beyond mapping styles. It changed the way scientific data was displayed.

© Peter Roehrich 2015

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Rivers, Mountains, Islands, Waterfalls

Tallis Eastern hemisphere comparative view of waterfalls, islands, lakes, rivers, and mountains.
A Comparative View of the Principal Waterfalls, Islands, Lakes, Rivers, and Mountains of the Eastern Hemisphere. 1850.(Ruderman)


This stunning comparative is a shining example of the 19th century genre. Published by John Tallis in about 1850, it serves as an excellent introductory piece featuring exquisite detail in vibrant color.

This comparative contains both single and compound exhibits, all primary and in the illustrative fashion. By single exhibit I mean a panel depicting a single class of geographic feature; on this comparative, the waterfalls, islands, and lakes panels are single. On the other hand, the mountains and rivers are shown together in a compound panel. The comparatives are primary in that they are the focus of the map, they are not a small inset on another projection. This chart is illustrative to the extent that it conveys to the reader a sense of scale, but the panels on it are not suitable for determining the exact dimensions of the features.

The positioning of the geographic features within a comparative panel is important, after all, it is the organization by size that makes them comparative. This view uses a descending overlaid pyramid sort for the mountains, an ascending valley sort for the waterfalls, and an inverted ascending valley sort for the rivers.

This chart’s layout provides a snapshot of the changes in 19th century comparatives. A pastoral scene at the top is reminiscent of an earlier style, while the compound mountains and rivers panel became popular mid century. Moreover, the Eurocentricity of the waterfalls panel–all but one are in Europe, with the glaring omission of Victoria Falls (of course, Victoria Falls was observed by Livingstone in 1855, so could not have been included)–gives way to a focus on Africa and Asia in the mountains and rivers panel, sort of. The geography of the mountains and rivers panels is eastward looking for the simple inescapable reason that the tallest mountains and longest rivers are in Asia and Africa. Despite the focus on Asian & African geography, the comparative takes a western vantage point. We can find this western perspective in two fashions: inclusion of European features and inclusion of European ‘cultural’ reference points. On the one hand, the Forth, Shannon, and Thames rivers occupy the position of the 3 smallest shown maps, presumably shown to give a European viewer a sense of scale; the same might be the case with the inclusion of  several small European mountains. Conversely, the balloon flights of Green and Gay-Lussac (the tiny specs above and to the right of the mountains) show a European bias to the extent that it documents Europeans’ mastery of the natural world.

The Tallis comparatives, both this one featuring the Eastern Hemisphere and its Western Hemisphere analog, are among my favorites, particularly those in color for their aesthetics and the elegant way the engraver packaged so much detail (oh, note the eruptions from Vesuvius and Etna)–achieved such data-density–into a small graphic without the aid of a computer.

© Peter Roehrich 2015