From what I've read and what I have discerned from my small collection of the Silent Teacher series of map puzzles, it appears that the line was started in the late 1860s or early 1870s by G.N.Tackabury of Canastota, N.Y. The earliest date that I can find is a copyright notice of 1872 by James Monteith. This copyright may refer only to the cross-sectional view that shows the comparative elevations across the center of the country.
The earliest puzzles have plain black paper on the backside and the maps used
were published by Tackabury. The U.S. maps only show rivers, mountain ranges and cities.
There are exercises for the student and a vertical bar indicating the
latitude of various cities of the world.
The next in the series have D&MC Wiggins New Haven, N.Y. printed on the
lower right corner. Sometimes, their name is covered by the green edge paper.
I don't know if D&MC Wiggins were the puzzle makers or simply
print publishers. These maps have no other indication of manufacturer and have
only a scroll on the title. The vertical latitude bar remains on the prints but has
been left blank. The exercises are much the same as the Tackabury series and would be
difficult without the latitude information. The examples that I own have maps or plain paper on the
backsides and show railroads in addition to what is on the Tackabury prints.
I have only come across one "Mrs. E. J. Clemens" map puzzle. Perhaps she took over the business briefly after her husband died, a close look at the maps gives some clues. Look closely at each of the Iowa state pieces. The first, (A) is from a Tackabury's and Iowa has three cities. The second, (B) is from a D&MC Wiggins and Iowa has five cities (note the rivers!). Next, (C) is from a Rev E.J. Clemens' puzzle and (D) is from the one Mrs. Clemens map that I have. Iowa from a C.E Hartman puzzle is identical to (D). The reverse of this puzzle is an advertisement for White Sewing Machines.
C. E. Hartman leaves no doubt about his (or her) place in the timeline. These puzzles
often have pictures of C.E. Hartman's building in Utica, N.Y. and advertise the line of puzzles
that they make. The imprint of the title & manufacturer's name is very similar to Mrs. Clemens' imprint, the
maps are virtually identical.