Maps are art with a purpose. -- Lloyd Brown

Martenet's 1860 Howard County Map
How Were They Made?
The maps were not the result of "surveys" as the term is used by surveyors today, with theodolites and chains, etc. The "instruments" used were an odometer wheel and a compass. This, of course, will always result in measurements too long, for the wheel must measure along the undulations of the ground—the hypotenuse of the triangle, if you will, instead of the horizontal side, which is what the map purports to represent. Nevertheless, given the economic realities of the day, the method met the need.

The work was tedious and weather-dependent, but continued throughout the year anyway. Rhodes wrote from Poolesville on January 17, 1866, "This continued delay is much to be regretted. Every day grows darker. Would it not be well for me to come to Baltimore to review the proof? I wrote to R T Bentley to send the proceeds of the two maps left with him, but as I have not since been to Rockville do not know that they have been sent. Will you please send me five or ten dollars." [sjm04-63016-5] And then two days later, "I have just reached Rockville. The additional corrections are on the Monocacy Chapel road to Dawsonville thence to Seneca Mills & thence on difficult roads to John T. Dufifs. I will not recapitulate as they are sufficiently distinct. I have obtained eight more subscribers. I am much fatigued in travelling through the snow, and am quite unwell. I will take a little tour through Clarksburg and Cracklin, and come to Balt Tuesday or Wednesday." [sjm04-63016-8]

Harford County notes
(Click to enlarge)
Dorchester County Notes
(Click to enlarge)
The Notes
The surveyor noted the compass courses and odometer readings for each bend in the road, supplemented by notes to assist the draftsman (then, spelled draughtsman!) in plotting same. The notes themselves varied in form from surveyor to surveyor. Some more graphic in nature, as illustrated by some of McCreery's notes for Harford County at left (note the reference to the Booth farm where John Wilkes Booth reportedly was born). [sjm04-63015-9] Others were tabular in nature, as illustrated by Dorchester County notes by Rhodes at right. [sjm04-63014-6] Apparently the buildings were just sketched in using the small details in the notes.

Details of towns took the appearance of the Poolesville notes on the previous page. The record is silent as to the process whereby names belonging to non-subscribers were selected for inclusion on the map.

(There are no dates on the note pages themselves, so it is impossible to determine how many miles were covered by the surveyor in a typical day. If there was such a thing as a typical day!)

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