The Principal Species of Wood: Their Characteristic Properties First Edition — Story, Setting & Ideas

Standardized Entry Format

Each species is treated in a consistent, almost tabular format. Entries open with nomenclature (common and local names), then locality, features of the tree, color and appearance of the wood, structural qualities, representative uses, weight per cubic foot, modulus of elasticity, modulus of rupture, and remarks. For example, the entry for Sweet Gum (Liquidambar styraciflua) lists heartwood as 'rich brown suggesting black walnut,' sapwood 'nearly white,' and notes that the wood is 'heavy, rather soft, strong, stiff, not durable when exposed.' The entry for Sour Gum (Nyssa sylvatica) describes its grain as 'fine' and its fibres as 'interlaced, therefore hard to work.' This structure allows quick comparison across species.

Mechanical Data and Sources

Snow includes numerical data for weight, modulus of elasticity, and modulus of rupture, often citing the U.S. Forestry Division. For Sweet Gum, he gives weight as 37 pounds per cubic foot, modulus of elasticity 1,700,000 (average of 118 tests), and modulus of rupture 9,500. Footnotes occasionally add field reports, such as a Texas & Pacific Railway engineer noting that gum ties held spikes well after five years. The inclusion of such practical testimony alongside laboratory averages reflects Snow's aim to serve users—engineers, builders, and woodworkers—who need both standardized numbers and real-world performance notes.

Illustrations and Visual Aids

The book contains 155 illustrations, with 138 original drawings. Plate 22, for instance, depicts foliage and wood samples of holly, boxwood, lignumvitae, and dogwood. The preface credits the drawings as having been prepared specifically for this volume. These visual elements complement the textual descriptions of grain and color, helping readers who may not have access to physical samples. The illustrations are not merely decorative; they are integral to the work's function as a practical identification guide for wood species.

Scope and Limitations

Snow explicitly limits his coverage to 'principal species' of commercial importance in North America. The excerpts show entries for Sweet Gum, Sour Gum, Cotton Gum, Holly, Boxwood, and Lignumvitae, but the full book likely covers many more. The author acknowledges that errors may exist despite careful checking, and he does not claim completeness. The remarks section often notes practical drawbacks: Sweet Gum 'shrinks and warps badly in seasoning,' Sour Gum is 'limited usefulness because difficult to work,' and large specimens of several species 'often have hollow butts.' These candid observations enhance the book's credibility as a working reference.

Snow's volume is best read as a reference to be consulted species by species rather than read straight through. The consistent entry format makes it easy to locate specific data, while the preface and introductory remarks provide context for the author's engineering perspective. Readers interested in the mechanical properties of wood will find the modulus values and weight figures especially useful, though the book also offers practical notes on workability and durability. For those new to wood identification, the illustrations and color descriptions offer a starting point for visual recognition.

I have sat with The Principal Species of Wood for many quiet evenings, its measured facts a steady hand on the shoulder. It reminded me of another, humbler companion. Both understand preservation—one of timber, one of specimens—as a form of gentle patience. A wooden block, a pressed leaf, each holding its story until someone turns the page. Notes on Collecting and Preserving Natural-History Objects — Key Ideas to Explore keeps that same silent company.