Corroborating this, Mr. Compton relates that while working in Barnes's shop in Forest Grove, Oregon, during the last illness of that noted bowyer, he came across a laminated bow made entirely of sap wood. Barnes stated that he had constructed it at the instigation of Will Thompson. The cast of this bow was slow, flabby, and weak. As a shooting implement it was a failure.
Taking two pieces of wood, one white and one red, each twelve inches long, I placed them in a bench vise and fastened a spring scale to the top of each. Drawing the sap wood four inches from the perpendicular, it pulled eight pounds. Drawing the heart wood the same distance it pulled fourteen pounds, showing the greater strength of the latter. When drawn five inches from a straight line, the red piece broke. The sap wood could be bent at a right angle without fracture.
It is obvious from this that the sap wood excels in tensile strength the red wood in compression strength and resiliency. In fact, they are reciprocal in action. The red yew on the belly of the bow gives the energy, the sap wood preserves it from fracture. It is, in fact, equivalent to sinew backing, and though less durable, probably adds more to the cast of the bows.
In our experiments with a catgut and rawhide backing, we have not found that they add materially to the cast of a bow, only insure it against fracture. On the other hand, sap wood and hickory backing materially add to the power of the implement.
The little red yew bow used in the previous experiment was backed heavily with rawhide and catgut. It then weighed ten pounds, but only shot sixty-three yards, showing a decrease in cast. But the backing permitted its being drawn to ten inches, when it shot a distance of eighty-five yards. A draw of twelve inches fractured it across the handle.
In a similar experiment it was shown that two pieces of wood of the same size, but one being of a coarse-grained yew running sixteen lines to the inch, the other a fine-grained piece running thirty-five lines to the inch, the finer grain had the greater strength and resiliency up to the breaking point, but the yellow coarse-grained piece was more flexible and less readily broken.
The question often arises, "How would an arrow fly if the bow is held in a mechanical rest and the string released by a mechanical release?" Such an apparatus would permit of several experiments. It would answer some of the queries that naturally pass through the mind of every archer. Question 1. How accurate is the bow and arrow as a weapon of precision, or as they say in ballistics, "What is the error of dispersion?"
Question 2. What is the angle of declination to the left of the point of aim in the flight of such an arrow?
Question 3. What is the effect of placing the cock feather next the bow?
Question 4. What is the effect of shooting different arrows? How do they group? Would not such a machine give accurate data regarding the flight of new arrows and help in the selection of shafts for target shooting?