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Sunday, 22 January 2017

GOOSE FEATHER AT 100X

GOOSE FEATHER AT 100X


A beautiful image of a goose feather taken with Ultraviolet light.

There are many close up or microscopic images of feathers on the internet, mainly for artistic reasons and not very informative for the type of feather one is looking for.

With the help of the excellent technician Mark Wallwork at Falmouth University and having access as an Associate Lecturer  to the “Marine and Natural History Photography” labs, I had the chance to analyse and see the structure of the goose feather and explore the properties of this famous   feather in the medieval history,.

It is very important   from the beginning to set the terminology and refer to the equipment I have used for the easy understanding of this article by the reader.

*The OUTSIDE or SMOOTH side of the feather is the side that faces the sky when a bird flies.
*The INSIDE or ROUGH side of the feather is the side that faces the ground when a bird flies.

*To increase the detail of the microphotography many different filtrations have been used and different wavelengths of the light spectrum. So, while the feather is white , it will appear with darker colours.

  • The equipment used are:
   -Zeiss microscope Axio Scope A1 with reflected light at 100X
   -Zeiss microscope Axio Lab A1 with trasmidet light at 100X
   -Leica microscope with Ultraviolet light 100X
   -Nikon D7000 camera. All original images set to RAW



Image 2, inside - backlighting



Image 3, inside - even illumination

In image 2 & 3 we see the inside or rough side of the goose feather. Most of the feather’s structure is  on the feathers surface and quite rough and we can identify the barbs and the barbules and the way they hook. This is nature’s velcro. We can pull them apart and we can join them together again.
If you stroke with your finger this side of the feather you will understand why it is also called rough.




Image 4, outside - backlighting



Image 5, outside - backlighting



Image 6, outside -even illumination



Illustration 7



Image 8, outside - top lighting


In image 8 we see again the outside or smooth side of the goose feather, focusing on the top of the feather. The distance from the top of the barb to the barbule is large in microscopic terms, so much that the barbules fall complete out of focus. If you run your finger this side of the feather you will understand why it is called smooth.




Roger Ascham writes about fletchings and arrows in 1545 Toxophilus. 
I suppose his writings are well in  the longbow era and his technical details and findings are very valuable to us. He talks about heavy war arrows carried long, low triangular feathers, set on straight. 
We all know that the spinning of the arrow, left or right, depends on the choice of feathers it is fundamental for it’s stability and accuracy.

“In the brief history of arrow making”  at The Worshipful Company of Fletchers we read the following:

"Contrary to some belief it is not necessary to set fletchings on the slant in order to make the arrow spin. Provided that each feather is from the same wing, right or left, the arrow will spin because the feather has a rough side which produces lift and a smooth side over which air flows freely."

I always fletch my war arrows straight and they spin. The rough/inside side of the feather creates resistance on the wind, increases the pressure and the arrow spins. You can see that on a slow speed camera video of GREX LUPORUM at U-tube (  https://www.youtube.com/watch?v=L_WuH1QFnGs ). It flies straight for the first meter and then starts spinning.


That can be compromised if the feather doesn’t keep some of its valuable qualities and in our case  is mainly the resistance to dampness and wet weather. The goose feather, and I suppose other aquatic bird feathers can resist wet . The coherence of the feather’s structure has to be retained i.e. the rough and the smooth side and compactness.
In image 9 we see a Turkey and a Goose feather that I had placed in a wet environment and the difference between the feathers could not be more obvious.



Image 9 - From the top turkey and goose feather

The Turkey feather has completely collapsed it’s structure,  in contrast to the goose feather that has resisted the water. 
Now, an arrow with wet turkey feathers will fly badly for the obvious reasons and the fact that the feather will retain water will also make it be heavier i.e. slower. 
Most of the industry feathers are turkey and the  industry has develop some effective powders on the market to keep feathers dry in wet weather. 
Well they may do that but it will interfere with the rough/smooth properties of the feathers and therefore the  spin of the arrow.
I do have the knowledge that the turkey feather was not available in England until  17th century, but It goes without saying that the choice of the goose feather for war arrow fletchings in the medieval wars it was the best and practically the most effective.


Image 10 - young goose feathers



Image 11 - a small goose feather after a raining night.


SOURCES

*"Marine and Natural History Photography" Labs / Falmouth University.
*The Worshipful Company of Fletchers.
*Roger Ascham- Toxophilus. 1545 ce.
*The University of Waikato.
*Organic farm for the birds feathers / East Sussex, UK.


© Yiorgos Nikiteas




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