Archery in general
Part 2 of 2
Shooting straight up, such an arrow goes about three hundred and fifty feet high, and requires eight seconds for the round trip. This test was made by shooting arrows over very tall sequoia trees, of known height.
The striking force of a one-ounce arrow shot from a seventy-five pound bow at ten yards, is twenty-five foot pounds. This test is made by shooting at a cake of paraffin and comparing the penetration with that made by falling weights. Such a striking force is, of course, insignificant when compared with that of a modern bullet, viz., three thousand foot pounds. Yet the damage done by an arrow armed with a sharp steel broad-head is often greater than that done by a bullet, as we shall see later on.
A standard English target arrow rotates during flight six complete revolutions every twenty yards, or approximately fifteen times a second. Heavy hunting shafts turn more slowly. This was ascertained by shooting two arrows at once from the same bow, their shafts being connected by a silk thread, so that one paid off as the other wound up the thread. The number of complete loops, of course, indicated the number of revolutions. A sand-bank makes a good butt to catch them. In rotating, much depends on the size and shape of the feather.
Shooting a blunt arrow from a seventy-five pound bow at a white pine board an inch thick, the shaft will often go completely through it. A broad hunting head will penetrate two or three inches, then bind. But the broad-head will go through animal tissue better, even cutting bones in two; in fact, such an arrow will go completely through any animal but a pachyderm.
To test a steel bodkin pointed arrow such as was used at the battle of Cressy, I borrowed a shirt of chain armor from the Museum, a beautiful specimen made in Damascus in the 15th Century. It weighed twenty-five pounds and was in perfect condition. One of the attendants in the Museum offered to put it on and allow me to shoot at him. Fortunately, I declined his proffered services and put it on a wooden box, padded with burlap to represent clothing.
Indoors at a distance of seven yards, I discharged an arrow at it with such force that sparks flew from the links of steel as from a forge. The bodkin point and shaft went through the thickest portion of the back, penetrated an inch of wood and bulged out the opposite side of the armor shirt. The attendant turned a pale green. An arrow of this type can be shot about two hundred yards, and would be deadly up to the full limit of its flight.
The question of the cutting qualities of the obsidian head as compared to those of the sharpened steel head, was answered in the following experiment:
A box was so constructed that two opposite sides were formed by fresh deer skin tacked in place. The interior of the box was filled with bovine liver. This represented animal tissue minus the bones.
At a distance of ten yards I discharged an obsidian-pointed arrow and a steel-pointed arrow from a weak bow. The two missiles were alike in size, weight, and feathering, in fact, were made by Ishi, only one had the native head and the other his modern substitute. Upon repeated trials, the steel-headed arrow uniformly penetrated a distance of twenty-two inches from the front surface of the box, while the obsidian uniformly penetrated thirty inches, or eight inches farther, approximately 25 per cent better penetration. This advantage is undoubtedly due to the concoidal edge of the flaked glass operating upon the same principle that fluted-edged bread and bandage knives cut better than ordinary knives.
In the same way we discovered that steel broad-heads sharpened by filing have a better meat-cutting edge than when ground on a stone.
In our experience with game shooting, we never could see the advantage of longitudinal grooves running down the shaft of the arrow, such as some aborigines use, supposed to promote bleeding. In the first place these marks are inadequate in depth, and secondly it is not the exterior bleeding that kills the wounded animal so much as the internal hemorrhage.
A sufficiently wide head on the arrow cuts a hole large enough to permit the escape of excess blood, and, as a matter of fact, nearly all of our shots are perforating, going completely through the body.
Conical, blunt, and bodkin points lack the power of penetration in animal tissue inherent in broad-heads; correspondingly they do less damage.
Catlin, in his book on the North American Indian, relates that the Mandans, among other tribes, practiced shooting a number of arrows in succession with such dexterity that their best archer could keep eight arrows up in the air at one time.
Will Thompson, the dean of American archery, writing in Forest and Stream of March, 1915, says very definitely that the feat of the legendary hero, Hiawatha, who is supposed to have shot so strong and far that he could shoot the tenth arrow before the first descended, is manifestly absurd. Thompson contends that no man ever has, or ever will keep more than three arrows up in the air at once.
Having read this and determined to try the experiment of dextrous shooting, I constructed a dozen light arrows having wide nocks and flattened rear ends so they might be fingered quickly. Then I devised a way of grasping a supply of ready shafts in the bow hand, and invented an arrow release in which all the fingers and thumb held the arrow on the string, yet remained entirely on the right side of it.
After quite a bit of practice in accurate, later in rapid, nocking, I succeeded in shooting seven successive arrows in the air before the first touched the ground. I used a perpendicular flight. Upon several occasions I almost accomplished eight at once. I feel that with considerable practice eight, and even more, are possible, proving again that there is an element of truth in all legends.
It has long been a bone of contention among archers which element of the yew, the sap wood or the heart, gives the greater cast. To obtain experimental evidence, I constructed two miniature bows, each twenty-two inches long, one of pure white sap wood, the other of the heart from the same stave. I made them the same size, and weighing about eight pounds when drawn eight inches.
Shooting a little arrow on these bows, the sap wood shot forty-three yards; the red wood sixty-six yards, showing the greater cast to be in the red yew.
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?
Question 5. What effect does the time of holding a bow full drawn have on the flight of an arrow?
Question 6. What is the result of changing the weight of bows when the arrows remain the same?
Therefore, we devised a rest, consisting of a post set firmly in the ground, with a rigid cross arm and a vise-like hand grip. This latter was padded thickly with rubber, so that some resiliency was permitted. The bow was fastened in this mechanical hand by sturdy set screws.
At the other end of the cross arm a hinged block was attached, from which projected two short wooden fingers, serving the exact function of the drawing hand. These were spaced so that the arrow nock fitted between them, and when the string was pulled into position and caught upon these fingers, the bow was drawn 28 inches.
We adopted a system of loading, drawing and releasing on count, so that every shot was delivered with equal time factors.
Answer 1. Using the same arrow each time, with the target set at 60 yards, we found, of course, that the arrow always flies to the left when drawn on the left side of the bow, and that the angle of divergence for a 50 pound bow and a 5 shilling English target arrow was between six and seven degrees. Using a stronger bow this angle was increased,--also that with a weaker arrow the angle was greater,--but six degrees might be designated as the normal declination.
Answer 2. Every rifle expert knows what his gun is capable of, in accuracy, and an archer should know just what to expect of an arrow under the most favorable conditions. We therefore tried shooting the same arrow over the same course with the same release, under these fairly stable conditions: The day was calm. We shot an arrow ten times in succession and all the shots centered in a six inch bull's-eye; that is, none went out of a circle of this diameter. In other words, at sixty yards a bow can shoot arrows with an error of dispersion of no more than six inches. This is surprisingly accurate for a weapon of this sort, when it is considered that the best rifles of today will average between one and a half to three inches dispersion at 100 yards.
Answer 3. Placing the cock feather next the bow diverts the arrow to the left and causes it to drop lower on the target. The group formed by six flights was fairly close and consistent.
Answer 4. Out of nine arrows tested, five consistently made a good close group and four as consistently went out. The "outs," however, were uniform in the direction and distance they took. It would be possible by this machine to select arrows that would make co-incidental patterns. It is obvious, however, that differences in individual arrows are greatly exaggerated by the apparatus, because it was quite apparent by this test that any good archer could group these hits much closer than the machine delivered them.
Answer 5. In our shooting, we universally allotted five seconds for drawing, setting and discharging. However, when this time was increased to fifteen seconds, we found that our groups averaged seven and one-half inches lower. This shows the decided loss of cast incidental to long holding of the bow.
Answer 6. Placing a 65 pound bow in the frame immediately showed increased reactions throughout. The lateral divergence in arrow flight was increased to fifteen degrees and all individual reactions were correspondingly increased. The flight of the individual arrow was less consistent, showing plainly the necessity of a proper relation in weight between the arrow and bow,--a very essential factor in accurate shooting.
In conclusion, it seems to me that the machine naturally exaggerated the errors, for this reason. If the pressure of the arrow against the bow, in passing, amounts to two ounces, the arrow will fly a two ounce equivalent to the left, when the bow is held rigidly. An arrow that exerts four ounces pressure will fly correspondingly a greater distance to the left. But when the bow is held in the hand, there is considerable give to the muscles and the two ounce pressure is compensated for; thus, the arrow tends to fly straight. The four ounce arrow would with the same adjustment hold a correspondingly straighter course.
The vertical error, however, depends more on the weight of the arrow, on the feathering, the holding time, the maintainance of tension, and on the release of the bowstring.
There are many problems in the ballistics of archery that are unsolved, waiting the experiments of modern science. Empirical methods have dictated the art so far. In target equipment and shooting there is a wide field for investigation. Our interests, however, are more those of the hunter, and less those of the physicist.