This discourse on the wing has no pretensions to covering the subject completely. It differs from any discussion on eye-sign theory, which has not yet discovered scientific basis, for it takes advantage of the work that has been done on the theory of the wing of a bird by the constructors of aeroplane wings.

The object, as was sought in the eye-sign theory, is to discover physical characteristics as an aid to culling and as a guide to breeding. The final test will always be the basket; for pigeon fanciers herein lies the beginning and the end. However, often we are not satisfied with this test. Many are the race days that lose the good with the bad pigeons and in such  circumstances we must accept that luck and not quality plays a considerable part in the few birds to reach home in reasonable time.

Before we plunge into our subject it is clearly to be understood nothing here is in any sense original. The whole is the work of observers who have given a lifetime to the study of wings and here are assembled bits and pieces of their work. I am convinced they give a lot of help towards solving the pigeon fancier problems.

Having given the matter some thought it is for each one of us to decide how much or how little we need to take the wing theory into our reckoning when selecting reproducers or culling untried birds for potential racing merit.

Observations show three distinct categories of birds:
1 Flappers.
2 Semi-flappers, semi-gliders
3 Gliders

The flappers flap their wings and glide for very short periods during which they rapidly come back to the ground.

The semi-flappers, semi-gliders, usually flap their wings, but have longer periods of gliding, and come back to the ground, but over a much longer distance.

The gliders seem to make use of the air and to maintain themselves at a great height without falling except when the wind is behind; but even then, their descent is very slow.

Mullenhof established series for flappers which are as follows:
1 Quail series.
2 Pheasant series.
3 Sparrow series.
4 Columbine series.
5 Swallow series.
6 Swift series.

He thus advanced from the poorest flapper to the best by following a progressive scale of increase in quality; increase in speed of flight; and increase in its duration. His study did not go further, because be had found what he sought. Moreover, he spent the whole of his life in collecting this documentation.

But we who to-day know his works, can draw from his observations conclusions enlightening us in our pigeon problems. From observation of the Mullenhof series, one can lay down the following points:

1 The large flight feathers, at first greatly curved in sickle form, become progressively more straight to the point of complete straightness.
2 The concavity of the wing, at first very deep, diminishes to the point of almost complete, or complete, disappearance in the birds of the high series.
3 The rear wing, which at first represents the largest part of the total bearing surface, shrinks in the swift to the point of being no more than a small bunch of feathers.
4 The wing becomes longer as flight becomes more rapid, and more sustained to the point that, taking into account the weight to be lifted, the swift has a wing some three times longer than that of our pigeon.

Just as the skeleton of the wing tends to become longer books in the gliders, so it tends to become shorter in the best flappers. This fact automatically leads to the idea that there is a mechanism of flight and that there are different mechanical factors which produce different performances.

Who can question that the flap of the wing of the quail or the pheasant has a lower motor performance than that of the pigeon, and that the flap of the wing of the pigeon has a lower motor performance than that of the swift. The performances are different because the wing qualities are different. This appears so clearly in different species that it seems a self evident truth; but now to the study of the mechanics of flight as regards the racing pigeon.

Proceeding from the principle that the racing performance of a pigeon will depend on the quality of its wing flap, we shall study how the wing fulfils its function.

Zoologists have in the wing always seen an active section and a passive section, and their works indicate:
1 Active wing formed by ten primaries overlapping on the hand.
2 Passive wing, formed by feathers, secondaries, attached to the forearm.

We can adhere to this over-simplified classification, but add to it modifications required by more advanced observation.
1 The four large primaries 7, 8, 9, 10.
2 The first six primaries 1, 2, 3, 4, 5, 6.
3 The rear wing secondaries.
4 The skeleton of the wing.

1 is the creator of power; 2 the utiliser of power; 3 the regulator of the necessary lifting surface; 4 are the lever arms which will influence
the all out speed. On the form, quality and length of the last four flights will depend more or less the quality of the vortex created. On the size of the surface of the rear wing will depend a greater or lesser ease of lift.

Experience will show us that the rear wing with a large surface will powerfully help the pigeon at low speeds, but will progressively hinder it as its speed of flight increases.

The maximum surface is seen in the normal Right of the pigeon around its loft and the minimum surface is seen when racing. Where does the limit lie? It is a question of governing principles.

In the skeleton of the wing, the forearm and the arm are long in the poor flappers and especially in birds which seldom fly. They diminish in length as quality asserts itself to the point of being reduced to mere stumps in the swift, but unexpectedly they become long in the semigliders, semiflappers, with the large gliders showing the greatest development.

The wing in practice is divided into four parts:
1 and 2 The active wing, that is the ten large flight feathers, and here one is forced to make a division, for the roles of the first six flights and the last four flights are different.

The 7, 8, 9 and 10th flights are the producers of the energy which will be used by the first six flights. There are two distinctly different roles, both of which must be perfectly fulfilled in order to avoid a lack of equilibrium, harmful to flight.

3 The rear wing?inactive part in full flight. It acts simply as a bearing surface, its great surface is advantageous to the bird at the time of take?off and landing, but hinders and handicaps it in its flight on the wing.

4 The skeleton of the wing, that is the length of the lever arms, which will be moved by the wing muscles (and not by others). On this length will depend the angular speed, consequently the speed with which the tip of the wing will cover the inclined ellipse which it describes at each wing flap.

The question, the main question, is to see whether these views are correct, and whether the conclusions drawn from them correspond to the facts in the practical sense. To see whether they allow one to:
1 Judge the racing ability.
2 Judge the breeding ability.

For our purposes the following characteristics must beconsidered ?
1 Dimensions of the wing skeleton.
2 Variable thickness of the penetration edge (leading edge).
3 Depth of rear wing.
4 Alignment of rear wing.
5 Length of first flight.
6 Quality of large flights.
7 Form of last four flights.
8 Roundness of tip of the last four flights.
9 Alignment of the last four flights.
10 Straightness of the last four flights.
11 Length of wing.
12 Overlapping of last four flights.

1 DIMENSIONS OF WING SKELETON
The Mullenhof series shows us that going from the poorest to the best flapper, the forearm and the arm correspondingly diminish in length. In the Ostrich, for example, the arm is unduly long, there is maximum reduction of the forearm and hand. In the Albatross, that great navigator of the air, the forearm and arm are of the same length. In the long and rapid flighted Frigate, the arm is appreciably shorter than the forearm. In the Swift, the great master of speed, the arm is reduced to the state of a stump, and the forearm is very short.

A curious fact is that as the arm and forearm are reduced in length, the hand becomes progressively longer, and in the swift it is longer than the rest of the wing skeleton. These words: arm, forearm, hand, are not the only ones which are used in common for both man and bird. It is the muscles operating these parts of the wing, and not others, which will impart to the wing skeleton the rapid and complicated movements resulting from a flap of the wing.

Fanciers have thought that it was the pectoral muscles of the breast that ought to serve as a standard in evaluating the muscular potentialities of the pigeon, but they are the dorsal and pectoral muscle of the weight lifter. Without them, at the takeoff and on landing, where the muscular effort is greatest, the body might be deformed, and consequently cause disturbance in the internal organs.

But the pectorals only assume this role at the take?off and on landing. In full flight, as soon as the pigeon has assumed its course speed, their role becomes nil or almost so, a fact which demolishes the idea that development of the muscles of the sternum plays a preponderating role in the motor output of the wing flap.

In full flight, the united muscular effort is very small. This is a truth which is the basis of a proper understanding of the Wing Method, and which Pigeon fanciers must take to heart. It is a question more of utilisation than of hard work, and the quality of this utilisation will depend solely on the quality of the wing.

The wing muscles will activate the lever arms formed by the arm and the forearm, and on the proportional length of these lever arms will depend the speed at which the wing tip will cover that part of its ellipse corresponding to the time of compression, for your air?wing? engine, like all engines, has a time of compression, a dead time and a time of decompression. It is during the time of compression that the wing achieves (because it must achieve it) the maximum speed.

The power produced always corresponds to the old formula of mechanics: F equals MV1. M the mass does not change for a given individual in full flight, but V will vary according to the length of the lever arms. If you have a mass equal to four and a velocity equal to two, you will have
MV(2)=4 x 2 x 2 equals 16.
But if the velocity becomes 4 for the same mass, you will have:
4 x 4 x 4 =64.

You will see by this oversimplified calculation that the qualities, or so-called qualities, of the pigeon in hand are of very little importance compared with a possible increase in the speed. The shorter the lever arm, the greater is its angular  displacement. And since both length and angular displacement control this long lever arm, which is the hand finished with large primaries, to the wing tip, the active part in the output of the wing flap will cover its ellipse at a speed proportional to the increase in angular dip in the unit of time of 1/10th of a second.

If, from species to species one sees a progressive shortening of the arm and forearm, it is not difficult to see that in our pigeons there will be a very perceptible variation of this character from one individual to another. It is unusual, extremely unusual, to find a forearm shorter than 2". It is scarcely possible to find a forearm larger than 3 1/4.

The variation, seen from this particular angle, is enormous and easy o verify. This is easier than other wing characters which have to be measured in quite small fractions of an inch. We will deal with the forearm first because the arm is much more difficult to measure, and, with a few possible exceptions in certain pigeons, comparative values of the arm and the forearm scarcely vary.

Some 30 to 40 years ago, pigeons with a forearm of 3 1/4 in. were not rare, and those of 2 3/4 in. formed the great majority. Today, pigeons of the former type have disappeared and the latter are extremely rare. You have to handle 50 to 60 pigeons to find a single arm of more than 2 1/2 in. This is not always the case, but often it is so.

It is progressive adaptation of the organ to its function, and to the work required. It is the basket and only the basket which has done this. Often, old pigeon fanciers won't have it when they are told that pigeons of to?day are superior in speed and in duration of flight to those of the past. And yet this is true. There is no doubt that the ace pigeon of to?day possesses qualities superior to those of yesterday, suggesting that those of to?morrow will be superior to those of today.

It is a question of becoming adapted or of perishing, the great fliers make the life of the mediocre ones more and more difficult and the others are killed at increasingly short intervals. For us there is no doubt that we must breed with the aim of the shortest possible forearm and for the time being work to obtain a forearm of 2". Fanciers must watch out for the pairing, since the character is fleeting and disappears at the slightest opposition, that is in crossing with a longer forearm. If only one of the partners has this quality, it is necessary to breed scientifically in order to fix it. It is well worth the trouble.

It is very easy to dissect a wing of a dead pigeon and measure accurately the arm and the forearm; but this is not so easy with the living animal, especially when the part to be measured is covered with feathers. Two pigeon fanciers helping each other can arrive at the same or almost the same result, but for this character it is not a matter of small fractions of an inch, and the simplest thing to do was to find a practical means of measuring, especially the forearm, within a fraction of an inch.

In order to measure the forearm, place the tip of the index finger of the right hand on the extremity of the forearm, that is on point B. Let the outer part of wing drop naturally on to the index finger and the small projection at C will be felt on the first joint or at the junction between the first and second joints. This is about equal to 2 in.  at the junction of joints. The first joint is that which is in direct contact with the hand. This is a simple method and after a little time requires a fraction of a second for examination.

In the relationship of the parts of the lever arm there is one thing which needs to be noted, for there is a difference with the human arm. In the bird the extremities of the arm and forearm are joined by a powerful ligament, with the result that this part of the wing looks like a triangle. There is then in the bird less independence of movementthan in man, but one cannot help being filled with admiration at the flexibility, elegance and beauty of the movements whose impulsion comes from this triangular combination.

2 THE LEADING EDGE
When the experiments in wind tunnels made it clear that a curved surface gave a better result, or rather that the air offered less resistance to its penetration, the problem of thin blades was considered. The study of vortices however showed that there was a kind of penetration between layers of air, and not a cutting by thin blades. It also made clear that the layers of air moving to the rear were
driven back beyond the moving body itself, thus eliminating any counter pressure, thus no longer encountering the pressure of these layers of air, the solid body met with less resistance to its advance. It was from these observations that the science of aerodvnamics and research in aerodynamic forms evolved. In considering the ideal shape for a pigeon, the factors are:

(1) The pigeon does not slip horizontally through the air;

(2) The escape of the compressed air takes place through the extremity of the last four quills, at the elevation of the wing, and not towards the rear.

In flight, according to the momentary speed, the body of the pigeon oscillates above or below the horizontal, assuming almost vertical direction at the take off and on landing. This oscillation takes place around the point situated between the two shoulders, a fact which should not displease the advocates of equilibrium in the hands. It therefore does not seem, at first sight, that this question of aerodynamics has anything to do with the performance of the flight.

However, if one examines closely a wing flap, if one breaks it down and analyses it as did Marey, or if one makes a synthesis, or if one examines it by means of a slow motion film, one sees that the edge of the wing is at each wing flap carried forward. It is this part which attacks the layer of air and on the roundness of this part will depend more or less easy penetration.

Here we are faced with the true case for observation of aerodynamics. The penetration will be all the easier the more round the form of the forepart. It might be thought that the thickness of the forward edge would depend on the thickness of the wing muscles, but by looking at the previous illustration it will be seen that by the very construction of the wing, these muscles are carried towards the rear. It is, therefore, something quite different.

Each wing character has a different role to play, and sometimes even several roles. If the speed is regulated by the respective dimensions of the lever arms, which gives "short forearm" a clear characteristic of speed, then the thick forward edge is itself characteristic of the postponement of fatigue.

Thus, this quality is especially found in good longdistance pigeons, and by them I mean those which fly 10 and 12 hours without touching down. The lower muscular expenditure required at each wing flap has an effect which is easily explained by what has been said above. Unfortunately, we are here dealing with the most elusive character among all those we have to breed. It disappears with disconcerting ease. One must be able to mate a male and female both possessing it in order to be able to fix it in the descendants. In the first pairing, done any other way, it disappears as though by magic.

Fanciers may ask: "What is the most important character of these two just discussed?" A good forward edge and a defective end wing is a failure, but a good end wing and a thin forward edge can give reasonable results over short distances. In the case of long?distance racing, a complete wing is needed, but the clearest characteristic is the thick forward edge.

If you were able to assemble the first 20 prize winners of each of our national competitions, and the first 20 of a club speed competitions, you would notice: In the first lot you would probably have 100% pigeons with a thick forward edge. In the second lot you would have a very large majority of pigeons with a thin forward edge and some with a thick forward edge.