Sunday, 30 March 2014

Voyaging southward from the Strait of Magellan (1924)

Here is a copy of Rockwell Kents memoir of his sea journey in South America,Voyaging southward from the Strait of Magellan (1924).

Thursday, 27 March 2014

The Golden Ratio (Divine Proportion)

The truncated octahedron is an Archimedean solid with 8 regular hexagon faces and 6 square faces.Here is Leonardo da Vinci's rendering of this shape in the 1509 treatise by Luca Pacioli De Divina proportione (divine proportion) including both mathematical and artistic proportion (HERE).




  

Wednesday, 26 March 2014

Satsugu enso roku (1881)

The Internet Archive is an unusually rich source of high quality visual materials if you are prepared to search a little bit (I have found that using broad search terms such as "graphic" and "pictorial" uncovers the best material).

For example, here is Satsugu enso Roku, a stunning Japanese volume on tobacco growing from 1881.
The following notes are included in the volume:

Satsugu enso Roku (Tobacco Growing in Satsuma and Osumi Provinces).
5 vols in 1 (712pp). 156 figures in color, maps, charts, tables.  
Tokyo 1881.

This is a scientific work of that period and covers all phases of tobacco culture. It completely illustrates and discusses such subjects as morphology of the tobacco plant, planting, handling and care of seed beds, transplanting, weeding, use of wheat as a "nurse" crop, insect pests, tobacco diseases, harvesting, curing, etc. There is also an interesting illustrated section on the history of smoking.

The well known American botanist H.H. Bartlett says that "It is probably as interesting a monograph of a single crop plant as any nation could show at the same time."

It is lavishly illustrated with 156 figures in colour, most of which occupy a whole page, and many are tipped in and folded. Some of the illustrations of tobacco leaves are in natural size. Some of the illustrations are interesting from the view-point of printing. From a note by the author it seems that the outlines were printed from metal, colors were added with wooden blocks and some of these were overprinted by lithography for improvement. Bartlett says, "All in all, the printing of this copiously illustrated work with its effective coloring was a marvel of technical ingenuity".   

There is a ten - page English summary.






Friday, 21 March 2014

An Evening Walk in Ashton Park


The Brain of Hermann Von Helmholtz (April 14, 1899)



Original Science paper HERE.
Image of Brain from HERE
More on Helmholtz HERE.

Thursday, 20 March 2014

The Crayfish

Thomas Henry Huxley's monograph on the Crayfish HERE.


Dance of the Bumble Bee

Karl von Frisch (1886 – 1982) was an Austrian scientist who won the Nobel Prize in Physiology or Medicine in 1973 for his work on the sensory perception of the honey bee. One of the things he did was work out the meaning of the waggle dance by which bees indicate distance and direction of food. 


 A diagram from his book A Biologist Remembers (1957) HERE. And his Nobel prize speech.

Sunday, 16 March 2014

The elastic skin which is water's epidermis.

Ordinary water displays a strange property which is known as surface tension - it is almost as if water has a 'skin' of its own. 

From the novel Exploits and Opinions of Dr. Faustroll, Pataphysician by the French author Alfred Jarry (1873 - 1907), comes the following lyrical piece on the strange phenomena of  surface tension.  It is dedicated, quite rightly, to the English scientist C.V. Boys, who famously lectured on the science of surface tension and soap bubbles.
  
To C.V. Boys
It is probable that you have no conception, Panmuphle, writ-carrying bailiff, of capillarity, of surface tension, nor of weightless membranes, equilateral hyperbolae, surfaces without curvature, nor, more generally, of the elastic skin which is water's epidermis.
The novel features the pataphysician Doctor Faustroll, a Circassian scientist who was born in 1898 at the age of 63, and who died the same year at the same age. His sidekick is a lawyer, Panmuphle, who narrates their adventures as they travel over a sea that is superimposed over the streets and buildings of Paris. The above is taken from an English translation by Simon Watson Taylor (HERE).


The following images from C.V. Boys volume of lectures on Soap bubles, their colours and the forces which mould them (1916) HERE.





Laetoli Footprints

About 3.6 million years ago a small group of bipedal hominids walked across a thin layer of volcanic ash on a sandy surface in what is now Laetoli in Tanzania. Their tracks were preserved by a second layer of volcanic ash, that later turned into a cement. In 1976 these footprints were discovered by a team of paleontologists led by Mary Leakey. The actual find was made by Andrew Hill (original Nature paper here). 

The chances of the above sequence of events happening are remote. To say the least.

The discovery of the Laetoli footprints are an outstanding example of the power of simple scientific observation. There was no need for any of the high-tech gizmos associated with modern high-energy physics. No GPS. No fancy computer analysis. There was no 'experimental design' as the events were a one-off. These footprints were recorded by a team of scientists and field workers who were diligently working in blistering heat, notebook in hand. They found the footprints by looking through the blinding glare at the sandstone or tuff surface of the ground. It is a lovely example of the power of intense seeing.

The discovery of the Laetoli footprints does not answer any of the fundamental questions about nature that big experiments like the Large Hadron Collider do. Nevertheless, from a parochial human point of view, these footprints and what they imply are probably more fundamentally important. 

Over the past 40 years this set of footprints have continued to be of keen interest to a wide range of scientists who are seeking to understand how humans evolved from ape like ancestors via bipedal hominids.  

A recent paper by Raichlen, Gordon, Harcourt-Smith, Foster and Haas uses the Laetoli footprints to carry out a nice piece of experimental anatomy. They got modern humans to walk in a sand track with a normal gait (extended-limb bipedalism) and with a more ape-like gait (Bent Knee Bent Hip - BKBH) and then compared the 3D shape and depth of their footprints in the sand from these two different ways of walking with those from Laetoli. They conclude:
These results provide us with the earliest direct evidence of kinematically human-like bipedalism currently known, and show that extended limb bipedalism evolved long before the appearance of the genus Homo. Since extended-limb bipedalism is more energetically economical than ape-like bipedalism, energy expenditure was likely an important selection pressure on hominin bipeds by 3.6 Ma.

Figure 1. Three dimensional scans of experimental footprints and a Laetoli footprint.

Image from HERE.






 
  

Tuesday, 11 March 2014

The Interference of Waves - 1807

The English polymath scientist Thomas Young (1773-1829) studied languages, medicine and physics and his name is immortalised in a series of experiments showing the interference of waves. He presented his work on the wave nature of light to the Royal Society in 1803.    

In a recent poll amongst physicists about which experiments they rated the most beautiful the following results were found:

1. Young’s double-slit experiment applied to the interference of electrons by Jönsson (1961).
2. Galileo’s experiment on falling bodies (ca. 1590).
3. Millikan’s oil-drop experiment (1909).
4. Newton’s decomposition of sunlight with a prism (1665–1666).
5. Young’s light-interference experiment (1803).
6. Cavendish’s torsion-bar experiment (1798).
7. Eratosthenes’ measurement of the earth’s circumference (ca. 250 BC).
8. Galileo’s experiments with rolling balls down inclined planes (ca. 1608).
9. Rutherford’s discovery of the nucleus (1911).
10. Foucault’s pendulum (1851).

Thomas was not well known as a communicator of his science, nevertheless he composed a two volume set - A course of lectures on natural philosophy and the mechanical arts- published in 1807 (HERE)

From Volume 1 is Thomas's description of a ripple tank demonstration of interference in water waves.

LECTURE XXIII - ON THE THEORY OF HYDRAULICS

p. 289


Many of the phenomena of waves may be very conveniently exhibited, by means of a wide and shallow vessel, with a bottom of glass, surrounded by sides inclined to the horizon, in order to avoid the confusion which would arise from the continual reflections produced by perpendicular surfaces, the waves may be excited by the vibrations of an elastic rod or wire, loaded with a weight, by means of which its motions may be made more or less rapid at pleasure; and the form and progress of the waves may be easily observed, by placing a light under the vessel, so that their shadows may fall on a white surface, extended in an inclined position above. In this manner the minutest inflections of the surface of the water may be made perfectly conspicuous. 

p. 290

When two equal series of circular waves, proceeding from centres near each other, begin their motions at the same time, they must so cross, each other, in some parts of their progress, that the elevations of the one series tend to fill up the depressions of the other; and this effect may be actually observed, by throwing two stones of equal size into a pond at the same instant; for we may easily distinguish, in favourable circumstances, the series of points in which this effect takes place, forming continued curves, in which the water remains smooth, while it is strongly agitated in the intermediate parts. These curves are of the kind denominated hyperbolas, each point of the curve being so situated with respect to its foci, as to be nearer to one than the other by a-certain constant distance. (Fig. 267.) 

Fig. 267. Two equal series of waves, diverging from the centres A and B, and crossing each other in such a manner, that in the lines tending towards C, D, E, and F, they counteract each other's effects, and the water remains nearly smooth, while in the intermediate spaces it is agitated.

Saturday, 8 March 2014

Royal Society of Arts

London is full of dozens of historical, cultural and architectural gems. The RSA is an example of all three. The RSA, or to give it its full title the Royal Society for the encouragement of Arts, Manufactures and Commerce, is based in John Adam Street very close to Charing Cross station. It was founded in 1754 and has included amongst its Fellowship over the years Charles Dickens, Adam Smith, Benjamin Franklin, Karl Marx, William Hogarth, Stephen Hawking and Tim Berners-Lee.



Monday, 3 March 2014

Cabrera's Law 1932

Angel Cabrera Latorre (1879 - 1960) was a Spanish-Argentinian zoologist and paleontologist. He was born in Madrid in 1879 and emigrated to Argentina, becoming an Argentinian  citizen in 1925. 

Cabrera worked at the National Museum of Natural Sciences in Madrid from 1902 until 1925. He specialised in mammalian anatomy and led scientific expeditions to Rif in 1919 and Western Morocco in 1921. He also participated in 1923 in another expedition to the western part of the Spanish Protectorate in Morocco which was was led by Royal Navy Admiral H. Lynes.

He published Fauna Ibérica; Mamíferos in 1914 which included his own illustrations. The book is available HERE and an illustration of a Lynx from that volume is below.





Cabrera also illustrated and published volumes on Mamallian Genera (1919)



Cabrera emigrated to Argentina in 1925 and became an Argentine citizen that year. He worked at the Institute of the Museum of La Plata as head of paleontology. From 1930 he was professor at the Faculty of Agronomy and Veterinary Medicine, University of Buenos Aires. He studied fossil fauna of Argentina including Megatherium, cetaceans, deer, camelids, Jaguars and marsupials. Cabrera also discovered the first Jurassic era dinosaur of South America in Patagonia.

Cabrera published extensively, including 27 books, over 200 scientific publications and more than 400 articles in national and international journals. Cabrera was a gifted scientific illustrator, often illustrating his own work and that of his colleagues.
 
In 1932 Cabrera published a paper on ecological incompatibility; La incompatibilidad ecologica una ley biologica interesante. Am. Soc. Cient. Argentina, 114(5/6) :243-260. (Biol.Abst.), that Ed Ricketts read and applied to the marine ecology he saw around him on the Monterrey peninsula. 

In the preface to his classic Between Pacific Tides Ricketts wrote a short Zoological Introduction that refers to this law; "In the same locality... directly related animal forms always occupy different habitats or ecological stations... Related animal forms are ecologically incompatible, and the incompatability is the more profound the more directly they are related."  The marine biologist Joel Hedgepath described it as a startling perception.


More HERE

Sunday, 2 March 2014

Animal Aggregations

Ed Ricketts attended the University of Chicago in the 1920's. One of the tutors he came into contact with was Warder Clyde Allee - a zoologist and ecologist who had a profound influence on Ricketts' approach to marine biology and ecology. Allee was the first to describe what has become known as the Allee Effect, defined as "the positive correlation between population density and individual fitness". 

In 2008 Franck Courchamp, Ludek Berec, and Joanna Gascoigne published a 270 page  monograph dedicated to the Allee Effect in Ecology and Conservation. In the preface they define the effect informally as the idea that "the more individuals there are (up to a point), the better they fare" and explain;

The Allee effect is an ecological concept with roots that go back at least to the 1920s, and fifty years have elapsed since the last edition of a book by W.C. Allee, the “father” of this process. Throughout this period, hardly a single mention of this process could be found in ecological textbooks. The concept lurked on the margin of ecological theory, overshadowed by the idea of negative density dependence and competition. The situation has appeared to change dramatically in the last decade or so, however, and we now find an ever-increasing number of studies from an ever-increasing range of disciplines devoted to or at least considering the Allee effect.
Warder Clyde Allee's classic from 1931 - Animal Aggregations. A study in General Sociology was published by the University of Chicago Press and is available to download in its entirety HERE.




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