ZACHARIAH JESS, A Compendious System of Practical Surveying, and Dividing of Land: Concisely Defined, Methodically Arranged, and Fully Exemplified. The Whole Adapted for the Easy and Regular Instruction of Youth in our American Schools. (Wilmington, Bonsal and Niles, 1799), 221 pages of text plus 151 pages of mathematical tables.

Jess was a schoolmaster in Wilmington and apparently taught surveying. He felt the existing texts focused too much on the theory and offered few examples. Jess wanted to change that. To avoid "swelling the work and increasing the price," he omitted giving descriptions of surveying instruments. His thinking was they are better understood from a combination of hands-on inspection and instruction from the teacher. The book then focuses on the mathematics of surveying, complete with examples and illustrations.

The first third of the text covers plane geometry and trigonometry, logarithms, and use of the Gunter's scale. The latter device, now rarely seen, was used for calculating by early navigators and surveyors. The mathematical instruction and examples are simple and cover only the elements necessary for angles and lines. This is followed by more specific examples relating to surveying and by problems in determining distances and heights using angles and baselines.

The student is then introduced to calculating the content of land. Intermixed with the instruction are some interesting tidbits of information. For example, "in laying out new lands, it is customary to allow 6 acres to every 100, for roads. The land, with this allowance, may be called Gross; and with this allowance deducted, it may be called Neat." The first instruction in content of land involves plotting onto paper, dividing into triangles, scaling bases and heights, and determining acreage by reference to the earlier instruction for calculating areas of triangles.

Jess then continues with the mathematical determination of land area. This involves using a traverse table to calculate rectangular coordinates. The latitude and departure of the courses are totaled and the results analyzed for error. If in a small survey the difference amounts to 5 links for every station there must be an error and a resurvey is needed. Once the difference is within limits the work is balanced by adding one half of the differences to the numbers in the less column and subtracting the same amount from those in the greater column. The area is then determined by the method of double meridian distance.

Instruction is next given for solving typical problems. These include dealing with an inaccessible station, determining areas adjacent to a watercourse or other irregular feature, and locating a corner by the method of intersection. The solution to the watercourse problem involves measuring offsets from a baseline. Where necessary, offsets are also taken from offsets for greater definition. An element of water boundary law appears in one example when the student is instructed that "offsets to all brooks, where the tide don't flow, must be measured to the channel." Another example has neighboring owners agreeing to a straight line boundary in favor of the former water-course border. The new line results in changed areas for the tracts, and the surveyor's duty is find which party has to compensate the other and for how much land.

Jess then gives a number of examples on dividing land and solving intersection problems. This is followed with directions to enlarge or diminish the size of a map, and how to survey with only a chain. This comprises the complete text although several mathematical tables follow.

A second edition was published in 1814. It adds the Pennsylvania Method of solving a D.M.D. area calculation, and finding the variation of the compass instrument by both the amplitude and azimuth methods. These both involve making solar observations. This new material was added by T. Hamilton of Philadelphia, and examined and corrected by S. Hilles of Wilmington.

Jess' Practical Surveying was an adequate text for classroom instruction at the turn of the 19th century. It faded with the introduction of similar works by Flint and Gummere, and never matched their popularity. For this reason it is comparatively scarce. Jess' book was never intended to compete against the more comprehensive treatise by Gibson.