Friday, November 13, 2020

ARCHITECTURAL GEOMETRY, A Rare Geometrical Record from Rural Devon, by Laurie Smith

 

 

Laurie Smith has written a new book: ARCHITECTURAL  GEOMETRY  A Rare Geometrical Record from Rural Devon.  

Here's the cover.



 

 

 

 

 

 

 

 

   

 

The book is about the many daisy wheels and other geometry found on the walls of a Devon threshing barn.
The barn, shown here, is owned by Richard Westcott, editor of The Three Hares, a Curiosity Worth Regarding. 
The image is #3, page 4.  



Richard Westcott, Laurie Smith, and their friend, the photographer and film maker Chris Chapman, examined and recorded the geometry on the barn’s walls -  over 169 separate geometric shapes.


This photograph is of a "divider scribed daisy wheel from the wall's inner surface." 

The image is #4; the quote is from page 4.

They researched the barn’s history, took measured drawings and photographs, and explored the geometry.

Then Laurie wrote this book. 

 
Like all of Laurie’s books it has beautiful diagrams. Clear descriptions accompanying the diagrams explain how the daisy wheels still visible on its walls governed the siting, layout, and frame  of the barn.

Image 39, page 26

This is 1of 5 of Laurie's illustrations showing the development of the barn section.     


He includes examples of similar geometries give context and nuance. 

Here is one of 4 daisy wheel drawings for the geometry of the Barley Barn, Cressing Temple, Essex, UK

 Image 27, page 19.

 

 

 

 

Along the way Laurie explains terms and forms which we rarely use today, including the use of a perch, pole and rod as measuring devices.  

He introduces the reader to the Trivium, the Quadrivium, and Whirling Squares. 

Part of Image 63, page 50 

 

He writes thoughtfully - and with humor -  about apotropaic symbols.  

 

 

At the end of the book Laurie considers how all of that geometry - 169 separate images - came to be scribed on the interior walls of a rural threshing barn. He suggests a 'geometry school'.  I agree with his theory: I have also found incomplete geometries drawn on plaster walls here in the States.


His descriptions encourage the reader to examine the image, think about what he's written, look again, and understand the geometry.

Here is what he says about this double daisy wheel:

"The image shows the geometrical precision of the divider-scribing, the scars of the divider pin at the twelve points around the primary circle and the compound damage caused at the symbol's axis by the passing of twenty four arcs."

Image and quote, page 59 


 

The book's copyright page includes this introduction: 

"Laurie Smith is an independent early-building design researcher, specializing in geometric design systems. Because the medieval educational curriculum included geometry he uses geometric analysis to excavate and recover the design systems of the past, a process he thinks of as design archaeology. He lectures, writes, runs practical workshops  and publishes educational articles on geometrical design that are available from his website."

www.historicbuildinggeometry.uk  

e laurie@historicbuildinggeometry.uk  


 I highly recommend this book to all who are interested in historic construction and geometry. Copies can be purchased from Laurie Smith in the UK or from me ($20.00 postage paid) in the USA. 

 

*All the photographs: the barn, the hand and the daisy wheel, and the 12 pointed daisy wheel in the barn shown here are by Chris Chapman, copied by me from the book for the purpose of this review. 

The geometry is by Laurie Smith, also copied with his permission.



 

Tuesday, September 22, 2020

Lesson 7, How to layout a frame with Lines

 Lesson 1 is here: https://www.jgrarchitect.com/2020/04/lessons.html

What's a Line?

A Line is a basic tool for layout and design.

Serlio, in 1520, used twine with a plumb bob as his Line. On  the frontispiece of his book, On Architecture, he drew his Line entangled in the metal scrolling. The end for tying is frayed.

 

 

 

 

Even through we now write 'line' without the capital L, we still use lines to keep our construction 'true' - straight, square, and plumb.


 

Patrick Kennedy, in Kentucky in 2020, used his line to keep his new stone wall straight. He tied his line to wood stakes. Rebar is also commonly used today.

photograph courtesy of P. Kennedy. 


Modern examples of using lines to keep construction square and plumb:
Checking a foundation's diagonals will ensure its rectangle is true. A square frame is easier to erect than one which is crooked.

A rectangle will have 4 square - 90* - corners if its diagonals  are equal. Here the far rectangle is not true. The diagonal is too long. It  should meet the corner at the upper spot.

Plumb lines ensure that walls are true or plumb: straight up and down, 

If an existing wall is not true the framer must know in order to compensate for the discrepancy. Here the plumb line with its  bob on the bottom shows that the foundation wall slopes.


How lines were used historically in construction can be seen in the frames of buildings built for utility. No one was showing off - just getting the job done - using what was ordinary.

Tuckahoe Plantation., Virginia

Cabins for enslaved people c. 1750.


 

 

This is minimal housing. We are lucky it survived.

 

 

 


 

 


Its geometry:

1)   A line - a length of twine - could have been used to layout the 2 square units.
Lesson 5 and Owen Biddle's Figure H show the steps. ,

 

The builder could have been laid out the foundation knowing only where to site the cabin and how big it would be. He didn't need drawings. He could set his foundation and lay the floor using only his Line and some pegs.

 

2 - The Lines measured the diagonals: if they matched the 2 squares were true. The diagonals also crossed at the center of each unit, locating the fireplaces, doors and windows.

 

The cabin floor could have became the framing floor. The Lines necessary for framing could be marked with a chalked line. 

Carpenters today build this way: they use the floor of whatever they are building as their framing floor. When the frame is ready it is lifted into place.

The square and its lines determine the wall height (red arrow). The 2nd floor is set at half the square. The roof begins as a square set above the wall. The roof pitch is the diagonals of the 2nd square. The chimney is 1-1/2 squares tall. 




 

 

 

 

 

No numbers were needed to lay out this cabin's frame, just practical geometry, some twine and something to mark the important points. The carpenters needed to understand practical geometry but not reading, writing or arithmetic.



 

 

 

 

The front elevation is an after thought. The plan and end elevation have already determined all locations.

 

 

Carpenters use center lines to locate windows and door. They then frame on either side of the opening. 

Masons, however, need to know where to end the row of bricks. The lines for brick or stone construction often end on the side of an opening.

 Owen Biddle's simple town house is a good example. It has 2 rooms up and down, plus a basement and entrance porch.

This layout could be drawn on the first floor just as the cabin could have been. A drawing might have been necessary for the front entrance with its fan light.  I have seen such drawings on wood which - when no longer needed - became roof sheathing.

Biddle's basic Lines locate the window location and height, the entrance size. 

His floor plan uses the Lines to locate walls and the fireplaces.  

The illustration was a guide for the 'carpenter assistant' so it is quite straightforward. It is the proportions that give the house presence.

Still, the house would be bare, spare as farmhouses are, without the details: the fanlight, the porch columns, the fretwork.

Other illustrations in his book use more complex geometries.

 

My introduction to the Tuckahoe Plantation cabin is here.\: https://www.jgrarchitect.com/2014/06/cabin-tuckahoe-plantation-goochland.html

When I teach Practical Geometry, we often lay out the Tuckahoe cabin with a line. The floor plan appears as we swing the arcs and mark the intersections.

Owen Biddle's town house is elegant, and very simple. A step by step analysis of the geometry is here: https://www.jgrarchitect.com/2015/11/owen-biddles-plan-and-elevation-for.html 

 

The previous posts in this series  Lessons 1-6  are :

 https://www.jgrarchitect.com/2020/04/lessons.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lessons-2.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-3.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4.html

https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4b-old-first.html

https://www.jgrarchitect.com/2020/06/practical-geometry-lessons-lesson-5.html

https://www.jgrarchitect.com/2020/06/practical-geometry-lesson-5-addendum.html

https://www.jgrarchitect.com/2020/08/lesson-6-rule-of-thirds-part-1_21.html

https://www.jgrarchitect.com/2020/08/lesson-6-rule-of-thirds-part-2-serlio.html

 

 



 
 

Tuesday, August 25, 2020

Lesson 6, Rule of Thirds, Part 2 of 2, Serlio

 

The posts in this series  Lessons 1-7  are :

 https://www.jgrarchitect.com/2020/04/lessons.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lessons-2.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-3.html

 https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4.html

https://www.jgrarchitect.com/2020/04/practical-geometry-lesson-4b-old-first.html

https://www.jgrarchitect.com/2020/06/practical-geometry-lessons-lesson-5.html

https://www.jgrarchitect.com/2020/06/practical-geometry-lesson-5-addendum.html

https://www.jgrarchitect.com/2020/08/lesson-6-rule-of-thirds-part-1_21.html

https://www.jgrarchitect.com/2020/08/lesson-6-rule-of-thirds-part-2-serlio.html
 
https://www.jgrarchitect.com/2020/09/lesson-7-how-to-layout-frame-with-lines.html