Brown's 'Brownian motion' revisited.It's microscopes at 10 paces. Two independent researchers have taken opposite sides in a duel over whether Scottish botanist Robert Brown Noun 1. Robert Brown - Scottish botanist who first observed the movement of small particles in fluids now known a Brownian motion (1773-1858)
Brown really saw in 1827 what is now called "Brownian motion Brownian motion
Any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations. It was named for Robert Brown, who was investigating the fertilization process of flowers in 1827 when he noticed a “rapid oscillatory " -- the ceaseless, jiggling movements of microscopic particles suspended in a liquid, caused by the impact of fluid molecules surrounding the particles.
Daniel H. Deutsch of Pasadena, Calif., sparked the controversy last year when he contended that the vigorous motion Brown had observed through his microscope resulted largely from causes other than bombarding Bombarding is the process of 'pumping' a Cold Cathode Lighting tube (otherwise called Neon Signs). Information
A detailed process of bombarding can be found here, Bombarding. molecules. In particular, Deutsch emphasized that because Brown's samples remained uncovered during observation, effects such as evaporation and vibration could induce the movements he saw (SN: 5/4/91, p.287).
This salvo caught the attention of Brian J. Ford Brian J. Ford (born 1939 in Corsham, Wiltshire ) is an independent research biologist, author, and lecturer, who publishes on scientific issues for the general public. He has also been a television personality for more than 40 years. of Eastrea, England, an expert microscopist who has actually worked with several of the microscopes that Brown himself used. "These microscopes are all beautifully made brass instruments," Ford says. "They're about 5 or 6 inches tall. They screw into the lid of the mahogany box ... in which the components are housed. Their high-power lenses are well capable of [resolving] a living bacterium -- but only if you use them properly."
Last month at INTER/MICRO-92, held in Chicago, Ford presented a 25-minute videotape showing the erratic movements of tiny carbon particles in diluted India ink, microscopic oil droplets in milk, and minuscule particles inside a pollen grain pollen grain
A microspore of seed plants, containing a male gametophyte. -- as viewed through one of Brown's microscopes. "It [presents] an instantly recognizable and highly detailed portrayal of Brownian movement Brownian movement or motion, zigzag, irregular motion exhibited by minute particles of matter when suspended in a fluid. ," Ford says. "If you just showed it at a student lecture and said, 'This is what Brownian movement looks like through a modern microscope,' nobody would even stop to question the fact."
Ford took particular care to duplicate Brown's observations of pollen grains from a plant known as Clarkia clark·i·a
Any of various annual, chiefly western North American plants of the genus Clarkia, several of which are cultivated for their showy red, purple, pink, or white flowers. pulchella. Each grain, about 50 or 60 microns wide, contains a thick liquid held in place by translucent walls. When Brown looked inside the pollen grains with his microscope, he could see tiny particles, each about 1 micron across, suspended in the liquid and constantly in motion.
Deutsch readily concedes that both Brown and Ford were seeing some kind of movement. But he insists that neither saw true Brownian motion. In a letter in the June 4 NATURE, Deutsch states: "I doubt the interpretation, not the observation. Particle motion in Brown's methodology is too vigorous by orders of magnitude to be proper Brownian motion."
Deutsch argues that for Brown's pollen grains, the presence of water alone causes a variety of effects, including rupture of the grains, that Brown didn't take into account. "There's a whole series of physical and chemical processes that take place," he says. "It all happens rather rapidly, and unless you're aware of these things "These Things" is an EP by She Wants Revenge, released in 2005 by Perfect Kiss, a subsidiary of Geffen Records. Music Video
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2. ... you miss them."
He adds, "If you were to compare what you see under Brown's microscope using his conditions and take the same solution and put it under a modern microscope, using modern techniques, then you would see something quite different."
"Deutsch is acting as if people from an earlier era were too dumb to know what they were doing, but Brown was a most precise investigator," Ford replies. Indeed, according to according to
1. As stated or indicated by; on the authority of: according to historians.
2. In keeping with: according to instructions.
3. Ford, Brown carefully checked into and discredited just the kinds of confounding confounding
when the effects of two, or more, processes on results cannot be separated, the results are said to be confounded, a cause of bias in disease studies.
confounding factor effects that Deutsch mentions.
Last year, Ford offered Deutsch a wager. "If he were willing to take the bet, I gladly offered to eat my hat if I couldn't [succeed in getting the images]," Ford says. "I did write to him to say that I had now done it and that I hoped they make hat-shaped gateaux in Pasadena."
But Deutsch isn't ready to concede yet. He's hard at work preparing a paper to present his own views in more details.