From Public Domain Review:
The American Woods, a collection of more than 1000 paper-thin wood samples representing more than 350 varieties of North American tree. Between 1888 and 1913, Hough published a total of thirteen volumes of the work, but died in 1923 before being able to fulfil his epic fifteen volume plan. However, a final fourteenth volume was published in 1928 using his samples and field notes compiled by his daughter.
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