The circular, square, and octagonal earthworks of Ohio / by Cyrus Thomas.

  • Thomas, Cyrus, 1825-1910.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: The circular, square, and octagonal earthworks of Ohio / by Cyrus Thomas. Source: Wellcome Collection.

    12/62 (page 10)
    circumference into equal parts can be found only by first ascertaining' the circumference ; in the second place it is not possible, oven with the utmost care and best instruments, that the angles should be precisely the same and the steps exactly equal throughout, where the top of the circular wall is from 4 to 6 feet wide. It was probably the intention of the authors that this should be taken as a hypothetical illustration. But why give an imaginary “Field Book 77 and example when they could have referred to any one of their own surveys % Why do they fail to give a single illustration from their actual work if they placed the full confidence in it which their words imply? Not only is this disappointing to the student of arehasology, but the illustration of their methods is not calculated to inspire confi¬ dence in the accuracy of their surveys. It is evident from the language of the note and the supplementary plan that the “300 feet77 refers to the chords and not to the arcs. As it is not presumable they had a chain or measuring line 300 feet long, the chord would have to be measured by steps, a task which, as any surveyor or mathematician knows, is far more difficult to accomplish than any work our authors were likely to un¬ dertake. It is therefore apparent that they have given an illustration which is impracticable and which is not drawn from their own work. Moreover, the doubts which these facts raise in our minds are not al¬ layed by a resurvey of the Liberty Township works, in connection with which the note and supplementary plan referred to are given. LIBERTY TOWNSHIP WORKS. For example, the .smaller of the two prominent circles of the Liberty Township group, shown on pb xx, to which reference has just been made and which they represent as a true circle, with a diameter of 800 feet (certainly a round number where great accuracy is claimed), is in fact an irregular ellipse of the form shown in Fig. 2. The longer di¬ ameter, measuring to the middle of the wall, as ascertained by the sur¬ vey, is 866 feet, and the shorter 748 feet, the difference between the two being 118 feet. This survey was made precisely in the manner sug¬ gested by Messrs. Squier and Davis, save that the chords were 100 feet each, except a gap of 313 feet where the wall is too nearly obliter¬ ated to be traced satisfactorily* this gap is indicated on the plat (Fig. 2) by dotted lines. The field-notes of this resurvey are given here, that the critical reader may have before him all the facts, so far as it is possible to put them in print, upon which our conclusions are based. Beginning at station 1 (see Fig. 2) at the end of the wall on the south side of the gateway leading into the large circle, the courses were run from station to station westward, northward, and around to the place of beginning.1 lrrhe measurements are always to be understood as to and along the middle ol the walls unless otherwise noted.