Popular Science Monthly/Volume 20/December 1881/A Map Review
| A MAP REVIEW. |
By FRANK D. Y. CARPENTER, C. E.
EVERY new scientific book is duly noticed, and every meritorious painting or other work of art receives its critical mention, but we have yet to see, in this country, any review of that combination of science and art—a geographical map. Such a map, worthy in more ways than one of the attention of engineer and artist, has just been completed in the Washington office of the geographical surveys of the United States Engineer Bureau, and as a posthumous publication of these surveys, now discontinued, its appearance may awaken a sense of regret over the end of an organization which was capable of producing such excellent results. It has already won the highest honors at the Geographical Congress of Venice, where the original drawing and a photo-lithographic proof were exhibited in September last.
This sheet was designed by Captain Wheeler, in charge of this work, to illustrate the methods of map-making, peculiarly American and adapted to our extensive territory, which have been developed in this country within the last quarter of a century, through the successive mediums of the itineraries of exploring parties, the various boundary surveys, Whitney's California Survey, Clarence King's Fortieth Parallel Survey, Hayden's and Powell's geological surveys, and the geographical surveys and other frontier operations of the Engineer Bureau. The methods in question combine the rapid reconnaissance, the mountain sketch, and the barometrical height upon a precise geodetic basis, incorporating all reliable information attainable from other sources, especially the land-surveys, which give certain points in roads and streams, and the perimeters of valleys and areas of water. In the end we have a map of which the error is, in general, inappreciable, and the cost in time and money is comparatively insignificant. Yet so faithfully may the features of a country be portrayed in this way, that the map of Lake Tahoe, the subject of this note, is sufficient to guide the engineer in his projects, the geologist in his studies, the tourist on his travels, the soldier on his march, and the emigrant in his search for a home.
So much for its usefulness, which is the first and principal mission of a map. As a work of art, graphically delineating the configuration of a district of surpassing beauty and variety of scenery, it will, perhaps, possess greater interest to the ordinary observer than any scientific value of accuracy and completeness could give it. If a person were called upon to construct an ideal map which should group together specimens of all types of topographical form and the conventional signs known to the draughtsman, he could hardly derive from his imagination a chart more comprehensive than this. There is certainly nowhere else in our country an area of equal extent so diversified and broken. Extending from latitude 38° 45' to 39° 32', and from longitude 119° 33' to 120° 22', it reaches from the desert inland basin of Nevada to the timbered and grassy mountain-spurs—embraced by the multitudinous forks of the American River—with which the Sierra Nevada range descends into the Sacramento Valley of California.
Lake Tahoe is a sheet of water some ten by twenty miles in extent, situated high up in the heart of the Sierras. The mountain-range divides to receive the lake, forming a cup-like space in which its clear waters are gathered. On the map the lake is given the place of honor, in the center. Its surface, being six thousand two hundred feet above sea-level, is not far below the rim of mountains which inclose it, but which, however, slope to great depths in the Carson Valley on the east and toward the Pacific coast on the west. The range in altitude, from the lowest to the highest point on the map, is more than seven thousand feet, there being three mountains—Freel's Peak, Pyramid Peak, and Mount Rose—standing at three corners of the lake, which are upward of ten thousand feet in height. Thus the subject, taken as a whole, is an admirable one for cartographical expression and effect, the surrounding valleys and the blank expanse of water in the center constituting a ground from which the mountains rise in bold relief.
Nor, taken in detail, is it less worthy of study. The agricultural district with its checker-work of farms, the great round hills which cover the Comstock lode, the barren edge of the desert, the sharp and ragged peaks which are the sierras proper, the easy grades of the forest-clad slopes about the lake, the rocky shore, the sandy beach, the angular course of the mountain-torrent as it dashes between cañon walls, and its winding bed through the alluvial soil of the valley, are all given true to nature.
The draughtsman to whom this map owes its realistic appearance is Mr. John E. Weyss, a veteran of thirty years' continuous service as a topographer for our Government. In order to catch and preserve those characteristic traits of form and surface which it is so hard for one draughtsman to transmit to another, he visited the ground in person, and, from the summits of lofty peaks and other advantageous points, accumulated a series of sketches with the aid of which to restore a natural effect to the construction-plots of contour-lines as they came to his hands from the surveyors. The map is finished in hachures, a method which is more intelligible to the unprofessional eye than that of contours, and which, in this case, is made especially effective by a free and artistic handling of the subject. As that is the best map for popular use which, in its true proportions, presents the most exact picture of the country for which it stands, there is room, in a district accidented as this is, for many a felicitous touch and extra bit of shading not provided for in any of the schools of topographical drawing. In fact, the draughtsman who adheres too closely and conscientiously to Lehmann's or any other conventional diapason of shades is likely to construct a map whose geographical features are stiff, unnatural, and almost mechanical in their geometrical regularity, just as the writer who checks up every sentence by his text-books of grammar and rhetoric produces an essay with none but negative merits to recommend it.
Mr. Weyss accompanied General Michler, of the Engineer Corps, on his recent official mission to the different geodetic institutions of Europe, and, having seen the best that the Old World has to show, he still maintains that this is the finest geographical map ever made. Taking into consideration both the subject and the manner of its treatment, this claim is not an extravagant one. In one respect this has an advantage over the maps of the thickly settled European countries, upon which the utilitarian features of roads, villages, and other works of man are so numerous as to obscure the natural attractions of the land, and to give it the uninteresting appearance of a city plot; for too many right angles detract from the beauty of a map as well as from the charm of a landscape. While the advancing wave of civilization has touched the region around Lake Tahoe, it has not yet covered it, and there are districts near its bowlers which are still as wild and secluded as in the days of the first explorer. There is the Devil's Basin, impassable and almost unapproachable, a great area of rock, rent with chasms and dotted with myriads of lakes. On every hand tower peaks upon whose summits, on a cloudy day, the traveler can feel as lonely as on the tops of the Alps or the Andes. And toward the northern limit of the map lies the historic Donner Lake, where, in the early days, a band of emigrants starved to death in the snows of winter.
But the practical pioneer is setting his seal upon this land, and claiming it as his own. Already the mountain-sides are marked with road, flume, ditch, and saw-mill, and scarred with mine and tunnel, and this lovely tract, fittest of all for a national park, is becoming the home of lumbermen and stock-raisers. The track of the plow is seen in the fertile valleys. The excavated ground of the Virginia City mines shows in the distance. Along the Carson River, at regular intervals, the quartz-mills lie. Log-slide, flume, and railroad carry the lumber from the heart of the forest to the outer world. The Pacific Railway winds between the high cañon-walls of the Truckee River and then follows its circuitous course, through miles of snow-shed and tunnel, across the Sierra Nevadas. 'Westward from Lake Tahoe runs the old Placerville road, once the main route of travel between California and Nevada, and down the eastern side of the range, in and out with many an escalop, winds the stage-road of the famous Hank Monk. From Virginia northward runs the Geiger Grade, the subject of one of Bret Harte's poems. In Emerald Bay is the little island with the empty grave which old Captain Dick carved for himself in the solid rock before he sunk in the deep water of the lake, to rise no more. Upon the cliff which bears the great poet's name the natural portrait of Shakespeare, done in weather-stain and lichen, is plainly visible. So there is enough of man's interference within the borders of this map to lend human interest and topographical variety to the scene.
It is a subject of common remark among travelers that nowhere else have they found a spot at once so easily reached and containing so great a variety of the interesting, the beautiful, and the grand, as here adjacent to Lake Tahoe, and this map will accomplish a not unimportant mission if it serves to call attention to a region too often overlooked. Leaving the Pacific Railway at Truckee or Reno, a circuit of one hundred miles will include not only this district, but the silver-mines of Virginia City and the mineral waters of Steamboat Springs as well. Then, from the south end of the lake, it is an easy détour of but a few miles to the crest of Tallac Peak, which, as if for the especial convenience of the tourist, is surrounded by an epitome of all types of Western scenery, from the placid beauty of Fallen-Leaf Lake, reposing at his feet, to the desolate wastes of rock which extend in chaotic piles behind him.
The map of Lake Tahoe was begun in the summer of 1876, in which season a survey of the shores of the lake and the mountains immediately outlying was made by Lieutenant M. M. Macomb, of the army, and the writer. Dr. F. Kampf, Mr. Gilbert Thompson, Lieutenant S. E. Tillman, Mr. William A. Cowles, Mr. Frank O. Maxson, Mr. Anton Karl, and other engineers have contributed to the work at different times. In one respect it is still incomplete, and it is to be hoped that provision may yet be made for a series of soundings with which to illustrate the very remarkable configuration of the bottom of the lake. It is scarcely to be doubted that the geographical map of the future, and especially the geological chart, will portray surfaces below as well as above water. These could be drawn in contour-lines, either faint, broken, or in blue color, so as to indicate their submarine position. The "ripple-lines" with which shores are now sometimes represented are arranged at regular intervals, in curves which are regularly concentric, and they give no idea of the additional character which a map would derive from a real plot of its surface below water.
Since the interest and effect of a plot increase with the irregularity of the surface of which it is a copy, no known body of water excels Lake Tahoe in the instruction to be gained from such a survey. It is very deep in comparison with its narrow superficial extent, the few random soundings already taken showing a depth of over sixteen hundred feet, with indications that there are other crater-like depressions beyond any yet discovered. The absence of currents and other sub-surface agencies of disturbance has probably left the cliffs and canons beneath the lake as rugged and unworn as those above it. The western bank is apparently abrupt and even precipitous, while the eastern shore is more gentle in its descent. Thus these declivities correspond to the two mountain-slopes of which they are respectively prolongations. A hydrographic survey would trace them in their descent, fathom the unknown depths to which they go, and furnish information which would not only be of general scientific and perhaps economical interest, but would also reveal the geological secret of the structure of this wonderful basin in the mountain-top.
