The Pharmaceutical Journal
Vol 280 No 7506 p727
14 June 2008

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Watercress: 200 years of a great British teatime treat

Dinosaur trees and early fossil flowers

Transparency please: the story of colour film

Why is Beryl blue?

Watercress: 200 years of a great British teatime treat

This year marks the 200th anniversary of the first watercress farm in Britain. It was opened by William Bradbury in 1808 at Springhead, Northfleet, near Gravesend in Kent.

One of the necessary conditions for growing watercress is pure, mineral-rich spring water.

As its name suggests, Springhead was a good place to start.

Watercress was first cultivated commercially in Germany, from where it was introduced to France. Napoleon was apparently an enthusiastic consumer and he was not the first leader to fall under its spell.

The Greek general Xenophon insisted his soldiers eat watercress before battle to increase their strength and vigour. Roman emperors believed it helped them to make bold decisions and even earlier, around 400BC, Hippocrates is said to have ensured a plentiful supply was available for the patients in his hospital by growing it in a nearby stream.

The heyday of British watercress was probably in the Victorian period when the spread of the railways helped to ensure its availability across Britain. It could be bought from street traders who made up bunches to be eaten as they were or added to sandwiches. It was one of the first street foods to become widespread and popular.

The watercress industry thrived up to the 1950s but, as newer and more exotic salad ingredients took its place, the “great British teatime” treat of watercress sandwiches gradually faded to a much lesser role as a garnish. It became, for most of us, just a bit on the side of the plate.

However, having at least 15 essential vitamins and minerals, watercress can be considered a “superfood” and it seems to be gaining in popularity again. Apart from its peppery taste, said to come from mustard oils, watercress has, gram for gram, more vitamin C than oranges, more calcium than milk, more folate than bananas and more iron than spinach.

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Dinosaur trees and early fossil flowers

The Wollemi pine, also known as the dinosaur tree, was thought to be long extinct until David Noble of the New South Wales National Parks and Wildlife Service abseiled into a largely undisturbed narrow canyon less than 100 miles from Sydney and discovered a strange tree he did not recognise.

He took a fallen branch to identify and it turned out to be what we now call Wollemia nobilis. Fewer than 100 specimens remain in the wild but careful propagation is increasing its numbers.

This odd-looking tree does not have leaves attached by stalks. Instead, the base of the leaf wraps around a branch. The tree sheds complete branches instead of individual leaves.

Wollemia was considered part of a long lost evolutionary line at least 200 million years old. Fossil remains had been found all over Australia, New Zealand and even Antarctica. It has been placed in the family Araucariaceae with the kauri (Agathis australis) and the monkey puzzle tree or Chile pine (Auracaria auracana).

Mosses, pines and firs dominated the earth until the first flowering plants appeared. How and when that happened is still largely a mystery. The earliest flowering plant fossil so far has been named Archaefructus liaoningensis and was found in north east China.

Flowering plants or angiosperms are important to us all. They include almost all our food plants along with fodder for our livestock and the flowers in our gardens.

For many years researchers thought a type of magnolia was the first flowering plant but nowadays they prefer to talk of the various branches of evolution. Amborella trichopoda, which is found naturally only in New Caledonia, has been called the oldest living flowering plant. This and the water lilies (Nyphaeaceae) are thought to have been among the first two branches on the family tree of flowering plants.

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Transparency please: the story of colour film

One of the latest “in” words for politicians and those who report on their activities is “transparency”. At last, it seems, our leaders have realised that we want to know much more about what they previously considered to be none of our business. Some observers seek “radical transparency”, in which all documents, discussions and decisions are made public — no secrets, no hidden agenda, everything in the open. They fear a lack of transparency can lead to corruption.

We are, of course, used to our lives becoming ever more transparent as surveillance equipment, communication systems and database technology erode our privacy. Audits and inspections have become a significant part of our lives. We are continually checked and assessed, so why should the checkers not be checked?

But there are other definitions of transparency. In optics it suggests the transmission of light through a material. In graphics it refers to overlaying images and translucency. And photographers who have not yet completely sold out to the digital age still use transparency or slide film. We hope this will not follow Polaroid film into a museum.

The earliest colour slides were made using the autochrome process but these were fairly dim with relatively poor colour resolution. Kodachrome arrived initially as 16mm movie film in 1935 and our familiar 35mm film a year later. Other well known makes followed.

Amateur use of this new film started in the 1940s, although it was expensive and needed new projection equipment. Colour print film took over by the late 1960s although transparencies were still preferred by some photographers for their sharpness and better colour reproduction.

Until recently most publishers of commercial and advertising media still demanded slides or transparencies for books and magazines but high resolution digital images are taking over there as well.

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Why is Beryl blue?

Captain (later Vice-Admiral) Robert Fitzroy sailed with Charles Darwin on HMS Beagle. While reading an account of his life I came across a description of a glacier with ice of “Beryl blue”. Who is this Beryl, I wondered? And what makes her blue?

It seems that beryl is a mineral, beryllium aluminium cyclosilicate, that occurs in a variety of colours. Many are used as gemstones, the most popular and valuable of which is the emerald, which is green beryl.

Pure beryl is colourless but traces of impurities give it various shades of blue, pink, purple, yellow, orange, brown and red. A peach form is called champagne beryl and a strawberry-red variety is known as bixbite. Beryl blue is, naturally, aquamarine.