The discrimination which is made between animals and objects portrayed simply as such, and as supernatural or mystic, is shown in the many illustrations of Ojibwa and Zuñi devices, in which the heart is connected with a line extending to the mouth, and those of the Ojibwa and the Dakota, where the spirals indicate spirit or wakan. Animals are often portrayed without such lines, in which cases it is understood that they are only the animals in natural condition, but with the designations or determinatives they are intended to be supernatural. Among the Ojibwa animals connected with certain ceremonies are represented as encircled by a belt or baldric, an ornamented baldric of the same character being used by the participants in the ceremonial chant dance; so that the baldric around the animal determines that the figure is that of a supernatural and mystic, not an ordinary, animal. This is an indication of the start from simple pictography towards an alphabet by the use of determinatives as was done by the Chinese.
It is not believed that much information of historical value will be obtained directly from the interpretation of the petroglyphs in America. The greater part of those already known are simply peckings, carvings, or paintings connected with their myths or with their every-day lives. It is, however, probable that others were intended to commemorate events, but the events, which to their authors were of moment, would be of little importance as history, if, as is to be expected, they were selected in the same manner as is done by modern Indian pictographers. They referred generally to some insignificant fight or some season of plenty or of famine, or to other circumstances the interest in which has long ago died away.
The question may properly be asked, why, with such small prospect of gaining historic information, so much attention has been directed to the collection and study of petroglyphs. A sufficient answer might be submitted, that the fact mentioned could not be made evident until after that collection and study, and that it is of some use to establish the limits of any particular line of investigation, especially one largely discussed with mystical inferences to support false hypotheses. But though the petroglyphs do not and probably never will disclose the kind of information hoped for by some enthusiasts, they surely are valuable as marking the steps in one period of human evolution and in presenting evidence of man’s early practices. Also though the occurrences interesting to their authors and therefore recorded or indicated by them are not important as facts of history, they are proper subjects of examination, simply because in fact they were the chief objects of interest to their authors, and for that reason become of ethnologic import. It is not denied that some of the drawings on rocks were made without special purpose, for mere pastime, but they are of import even as mere graffiti. The character of the drawings and the mode of their execution tell something of their makers. If they do not tell who those authors were, they at least suggest what kind of people they were as regards art, customs, and sometimes religion. But there is a broader mode of estimating the quality of known pictographs. Musicians are eloquent in lauding of the great composers of songs without words. The ideography, which is the prominent feature of picture writing, displays both primordially and practically the higher and purer concept of thoughts without sound.
The experience of the present writer induces him to offer the following suggestions for the benefit of travelers and other observers who may meet with petroglyphs which they may desire to copy and describe.
As a small drawing of large rock inscriptions must leave in doubt the degree of its finish and perhaps the essential objects of its production, it is requisite, in every instance, to affix the scale of the drawing, or to give a principal dimension to serve as a guide. A convenient scale for ordinary petroglyphs is one-sixteenth of actual size. The copy should be with sufficient detail to show the character of the work. It is useful to show the lithologic character of the rock or bowlder used; whether the drawing has been scratched into the face of the rock, or incised more deeply with a sharp implement, and the depth of such incision; whether the design is merely outlined, or the whole body of the figures pecked out, and whether paint has been applied to the pecked surface, or the design executed with paint only. The composition of paint should be ascertained when possible. The amount of weathering or erosion, together with the exposure, or any other feature bearing on the question of antiquity, might prove important. If actual colors are not accessible for representation the ordinary heraldic scheme of colors can be used.
That sketches, even by artists of ability, are not of high value in accuracy, is shown by the discrepant copies of some of the most carefully studied pictographs, which discrepancies sometimes leave in uncertainty the points most needed for interpretation. Sketches, or still better, photographs are desirable to present a connected and general view of the characters and the surface upon which they are found. For accuracy of details “squeezes” should be obtained when practicable.
A simple method of obtaining squeezes of petroglyphs, when the lines are sufficiently deep to receive an impression, is to take ordinary manilla paper of loose texture, and to spread the sheet, after being thoroughly wetted, over the surface, commencing at the top. The top edge may be temporarily secured by a small streak of starch or flour paste. The paper is then pressed upon the surface of the rock by means of a soft bristle brush, so that its texture is gently forced into every depression. Torn portions of the paper may be supplied by applying small patches of wet paper until every opening is thoroughly covered. A coating of ordinary paste, as above mentioned, is now applied to the entire surface, and a new sheet of paper, similarly softened by water, is laid over this and pressed down with the brush. This process is continued until three or four thicknesses of paper have been used. Upon drying, the entire mold will usually fall off by contraction. The edge at the top, if previously pasted to the rock, should be cut. The entire sheet can then be rolled up, or if inconveniently large can be cut in sections and properly marked for future purposes. This process yields the negative. To obtain the positive the inner coating of the negative may be oiled, and the former process renewed upon the cast.
The characters when painted with bright tints and upon a light-colored surface, may readily be traced upon tracing linen, such as is employed by topographers. Should the rock be of a dark color, and the characters indistinct, a simple process is to first follow the characters in outline with colored crayons, red chalk, or dry colors mixed with water and applied with a brush, after which a piece of muslin is placed over the surface and pressed so as to receive sufficient coloring matter to indicate general form and relative position. After these impressions are touched up, the true position may be obtained by painting the lines upon the back of the sheet of muslin, or by making a true tracing of the negative.
An old mode of securing the outline was to clear out the channels of the intaglios, then, after painting them heavily, to press a sheet of muslin into the freshly painted depressions. The obvious objection to this method is the damage to the inscription. Before such treatment, if the only one practicable, all particulars of the work to be covered by paint should be carefully recorded.