greg goebel / public domain
* VECTORS is an original newsletter of fact and commentary on aerospace, technology, science, and historical topics.
* The idea of a networked home has been around for about two decades, and so far it hasn't really taken off. There have been a number of problems with the concept, such as the lack of effective standards to make sure the different pieces of the network could play together; the need to wire up a house with the network, which not only made such schemes expensive but also inflexible; and the related problem of a certain lack of "scalability", in that the initial investment in the network was so big that it wasn't economical to set up a household network on an incremental basis, starting out with a single node and then expanding over time.
The widespread introduction of wireless technology opened the possibility of setting up a wireless home networking system, the vision being a control that could be installed simply by slapping a switchbox on the wall with double-sided sticky tape. In 1998, an industry organization, the "HomeRF Working Group" began to investigate the idea. HomeRF concluded that existing wireless systems weren't well-suited to implementing a wireless home network, and began to work on their own concept.
The HomeRF group disbanded without coming up with a solution, but in 2000 the Institute of Electrical & Electronics Engineers (IEEE, a professional association well known for its influential standards efforts), set up a working group designated "IEEE 802.15.4" to investigate "wireless personal area networks (WPANs)". The group released its initial spec in 2003 and issued an update in 2006. The spec is known more informally as "ZigBee 1.0" -- the name was cobbled together out of available domain names to give the spec a more interesting handle than "IEEE 802.15.4", and has no meaning other than those people want to read into it.
The IEEE is heavily into the wireless network business, having established the "IEEE 802.11" or "Wi-Fi" spec. Wi-Fi is broadly similar to ZigBee in that both provide a household wireless network, but the details are totally different. Wi-Fi operates at high data rates and necessarily uses a lot of power, while ZigBee operates at very low data rates and uses absolutely minimal power. Wi-Fi operates through a central hub, while ZigBee is a distributed network, with the intelligence residing in the nodes of the network.
Since ZigBee is intended to do things like control light switches, it can get by easily with a fiftieth of the Wi-Fi data rate. Since ZigBee boxes will often be battery operated and stuck in difficult-to-reach places, they need low power consumption to ensure that the batteries won't have to be replaced in anything less than a number of years.
ZigBee is not just seen as a way of turning lights on and off, however. ZigBee-based sensors could be put on all the windows and doors to let a central security controller know that all is quiet; this would permit any home to have a security system on a level near that of a museum. Sensors might also be fitted to track movements of residents in a house along with the temperature, humidity, and light levels in a room -- to adjust lighting, heating, ventilation, and air conditioning as needed. A ZigBee sensor could monitor the cat door to check the kitty's RFID tag and make sure racoons or possums don't get in. Outdoor sensors could monitor soil moisture and turn on the sprinkler system when needed. These are not basically new things, but ZigBee makes them much easier and cheaper to implement.
* A ZigBee node is built around a small silicon chip featuring a multichannel two-way link with a microcontroller, with the rest of the node built as per its function: a light switch, thermostat, sensor, or whatever, with nodes eventually built into appliances. The ZigBee network features autonomous organization: every time a node is installed, it seeks out neighboring nodes and links itself into the network -- though the owner has to authenticate the node to prevent a light switch from a neighbor's house from being added. Authentication may require no more than pushing a button, though it can be more sophisticated if the node has a display and keyboard. Installing the nodes is generally straightforward, and any homeowner should have no problem doing so except in specialized cases. In maturity, simple nodes will cost only a few dollars and there will be little overhead in buying and installing them, though setting up a central controller will be more expensive.
ZigBee operates at a maximum data rate of 250 kilobits per second. The messages are short and only sent infrequently, minimizing power use. ZigBee uses the same RF band as Wi-Fi, with communications based on "quadrature phase-shift keying (QPSK)", which is a digital signal in which pulses can shift timing in four ways, providing two bits of data with each shift. Each device in a ZigBee network can have an address in a 64-bit address space, though any particular network configuration will only use a 16-bit subset. Typically a ZigBee node will be asleep, unless it's taking a measurement or being polled by a controller. Even if a home is full of signals in the same band, the node will retry sending a packet at thousand times a second until it gets an acknowledge, and then goes back to sleep. Security was a basic consideration in the design of ZigBee, with the Advanced Encryption Standard (AES) used as a fundamental component to make sure that only the owner of the house or "trusted vendors" can get into any particular network.
A spec for ZigBee is all very well and good, but it's not enough to guarantee interoperability for ZigBee nodes from different vendors. An industry consortium, the not-for-profit ZigBee Alliance, was established in San Ramon, California, in 2002 to help establish conformance through enhanced specifications and testing procedures. It now has about 200 members, including companies dealing with semiconductors, consumer electronics, control systems, heating and air conditioning, lock makers, and so on.
* ZigBee, on the face of it, has substantial advantages over alternative home-control networks. The "X10" spec is in some use, but it requires dedicated wiring for the most part and can only handle 16 nodes max. The "Bluetooth" short-range wireless networking scheme could be used for a home network in principle, but it wasn't designed with that application in mind; for example, it doesn't have ZigBee's provisions for low-power operation.
ZigBee products are expected to show up at home improvement stores soon. Its advocates believe that ZigBee may make inroads into home-security networks, which have traditionally been based on proprietary technology, and should eventually appeal to commercial and industrial customers -- though commercial and industrial systems can have thousands of nodes, requiring careful planning in their implementation.
For the time being, the focus is on the home. Advocates believe they now have a solution that will finally make the smart home a reality, instead of an expensive contraption of questionable usefulness.
* If the end of the Cold War didn't result in peace breaking out all over, it still has had its benefits -- for example, a reduction in the stockpile of nuclear weapons maintained by the US. The irony is that doing so involves building new warheads. On 2 March 2007, the US National Nuclear Security Administration, the component of the US Department of Energy that handles bombs, announced the winner of a competition to design a "Reliable Replacement Warhead (RRW)". Funding hasn't been provided yet, but if Congress gives the go-ahead, work on the RRW may start in 2008.
Congress may well give approval since the RRW was partly the idea of Congress to begin with. The Bush II Administration wanted to build a nuclear bunker-busting bomb, but Congress was cool to the idea -- it might be too tempting to use the thing, particularly for an administration that seemed overly inclined to resort to force. It also would require testing, breaking the moratorium on test shots currently in effect.
The RRW design that was selected was produced by the Lawrence Livermore National Laboratory in California, over a rival design from the Los Alamos National Laboratory in New Mexico. It is a modification of a design that was tested four times in the 1980s, but was never put into production since it was judged too big and heavy. Now it seems well-suited to the RRW role. The modifications basically consist of changes to reduce cost and complexity while increasing safety and reliability; the subsystems that will be changed can be tested without actually performing a test blast. Some features of the rejected Los Alamos design, for example to prevent a stolen weapon from being used by terrorists, will be included in the Livermore RRW.
During the Cold War, warheads tended to small and complicated in order to put as many of them as possible on a single missile. Arms limitation treaties now mean that a single warhead is the norm, and so instead of building them small and tricky they can be built bigger, and much more robust. The ensured reliability of the RRW will allow stockpiles to be reduced further, since there won't be as big a need to maintain a margin of weapons to ensure sufficiency.
While the RRW does not seem to be very controversial, the Bush II Administration's plan to consolidate and modernize US weapons-making facilities into a "Complex 2030" is causing uneasiness. The new infrastructure will be able to turn out plutonium "pits" -- bomb cores -- more rapidly and will be more economical to operate over the long run. However, over the short run it will require massive investment. Los Alamos stands to be the big loser in the change, since the lab has been plagued in recent years by security and management problems and has been suffering from brain drain as the lab's expertise retires or quits. It was traditional US policy to maintain two weapons labs to provide some competition, but now that the nuclear arms race is over the redundancy seems simply wasteful.
The Bush II Administration has been prodding Congress to make decisions, pointing out that the US has been accelerating the dismantling of warheads to meet the treaty commitment with Russia of 1,700 to 2,200 strategic warheads deployed by 2012. The administration also points out that the other big nuclear players -- Russia, China, Britain, and France -- are also modernizing their arsenals. However, Congress seems inclined to think the matter out carefully.
* Before there was RFID, there was the barcode. Barcodes are now so familiar that it almost seems they've been around forever, but they're not all that old of an invention in themselves.
The seed of the idea appears to have arisen in the mind of a business student named Wallace Flint, who wrote a thesis in 1932 that envisioned an automated store in which customers would use punchcards to selected their purchases, with the products delivered to checkout by conveyor belts. The scheme would provide automatic tracking of purchases. It was the kind of idea that might have appeared in a futuristic cartoon at the time, but like a lot of wild ideas there were bits of brilliance in it, if someone had the perceptiveness to sort them out. The idea went quiet until after World War II. In 1948, a graduate student named Bernard Silver at the Drexel Institute of Technology in Philadelphia, Pennsylvania, overheard a conversation between an executive at a food company and a dean of the school in which the executive encouraged the dean to set up a research program for a system in which product data could be captured at checkout.
The dean was skeptical, but Silver was intrigued and got his friend Norman Joseph Woodland, a grad student and student teacher at Drexel, interested as well. Woodland suggested that they might use printed patterns that showed up under ultraviolet. The two men tinkered with the idea but couldn't get it to fly right: the ink wasn't stable, it cost too much, and so on.
Woodland still thought he was onto something. He quit Drexel and, living off a stock-market windfall, moved into his grandfather's apartment in Florida to work things out. He finally had a brainstorm, based on simply taking the dots and dashes of Morse code and extending them into long stripes. That left the problem of reading the "bars", but Woodland had another brainstorm to take care of that. He knew about the audio system used on movie reels, in which the sound was encoded on a strip on the side of the film, which was scanned by an optical system. The soundtrack on the film was modulated by variations in transparency; a light was shined through it and the varying light intensity picked up by a light sensor. Woodland decided to use the same scheme, except it would use reflected instead of transmitted light.
He then went back to Drexel and worked with Silver on a patent application. Silver figured out the appropriate codes while Woodland came up with a scheme of printing the bars as concentric circles -- what would become known as a "bull's eye" barcode -- so the barcode could be scanned in any direction. The patent application was filed on 20 October 1949.
Two years later, in 1951, Woodland got a job at International Business Machines, where he tried to promote the barcode concept. He worked with Silver to build a demonstrator for a barcode scanner, which was pieced together in the living room of Woodland's house in Binghamton, New York state. It was the size of a desk, and used 500 watt bulb to illuminate a barcode for a photomultiplier tube. It was big, clumsy, expensive, and the 500 watt bulb could cause eye damage; obviously, a better light source was needed.
The two men were awarded their patent in October 1952. Woodland continued to try to interest IBM in the scheme, and in response the company did hire a consultant who judged the idea had real potential -- but said the technology for it wasn't quite ready. IBM offered to buy the patent rights from Woodland and Silver, but their offer wasn't very generous. Philco made a better offer in 1962 and the two inventors took it. (Silver died the next year at age 38.)
Philco sold the patent rights to RCA, which would eventually pick it up and run with it. In the interim, other people were also grappling with the automated-ID problem. An engineer at Sylvania named David J. Collins was interested in automating the tracking of freight cars, coming up with a barcode-like scheme featuring orange and blue reflective stripes to create numeric digit codes. By 1967, Sylvania had a working system, with Collins telling the management that much more could be made of it. The bosses were only interested in the railroad market, however, and so Collins quit Sylvania to found a company named Computer Identics that he hoped would make a go of the idea.
The Sylvania system was introduced in 1970 and proved a bust, being too expensive at a time when the railroads were suffering economic problems. To the extent it was adopted, it also suffered from the fact that the barcodes became dirty and unreadable. Collins was moving forward by that time, with Computer Identics developing a scanner system based on the laser -- which had been invented a decade earlier, with affordable lasers now becoming available. The laser was the ideal light source, able to read labels from close up or relatively far away. A laser beam could scan a label multiple times along different paths to deal with damaged or dirty barcodes. New integrated circuit technology promised to make the electronics for the scanner system affordable as well. Computer Identics had two prototype scanners in industrial use by 1969.
With the technology ready, the next step was to find a startup customer to get things rolling. RCA was already hot on this track, with RCA officials attending a meeting of the grocery-store industry. RCA began research on the concept and drummed up industry support for it, helping set up an industry standards committee to set specifications, in particular for creating a common barcode spec. The committee was able to convince the industry players that the idea was technically and economically practical, and that government trust-busters weren't against it.
Still, the challenges were formidable, since the scanners would have to easily and reliably read barcodes, without demanding any training on the part of the user. The scanners would also have to be cheap enough to pay themselves off in a few years. In addition, the label technology would have to be cheap as well. At the outset, there would also be the problem that only a relatively small subset of products would have barcodes.
In the spring of 1971, IBM demonstrated the bull's-eye barcode at a grocery industry meeting, handing out barcoded disks of tin to attendees, with the barcodes scanned and the "winning" barcode getting a prize. IBM officials were at the meeting and got worried they might be missing out on a big market. However, somebody remembered that the inventor of the barcode actually worked for IBM, and Woodland was transferred to an IBM facility in North Carolina to work on the idea. (The patent established by him and Silver had expired in 1969.)
In 1972, RCA and the Kroger supermarket chain began a pilot test of a scanner system at a supermarket in Cincinnati, Ohio, using the bull's-eye scheme. It didn't work all that well, since the bull's-eye barcode tended to smear easily on printing.
In the meantime, IBM was working on a linear barcode scheme that would become known as the "Universal Product Code (UPC)". The linear barcodes didn't smear as badly. Although still other scanner schemes were considered -- starburst-shaped codes and machine-readable characters -- the UPC proved the most effective. It was formally adopted as an industry standard on 3 April 1973. The UPC features a 12-digit code, organized as two groups of six digits. The first digit is always 0 except for products that vary with weight, like meat; the next five digits are a manufacturer's code; the next five are a product code; and the last is a "check digit" to tell the scanner if the code has been scanned properly. The code has cues to tell the scanner which way to read it. The manufacturer's code and product code are obtained through a "Uniform Code Council (UCC)".
The first sale using a barcode system was a pack of chewing gum bought from a Marsh supermarket in Troy, Ohio, on 26 June 1974. Growth was slow in the first few years, however, since at least 85% of the products in a store's inventory had to be produced labelled with barcodes before the scheme would be economical. In the late 1970s that threshold was reached, and by the end of the 1980s barcodes were all but universal -- not just in supermarkets, but in any industry or application that needed to track inventory.
Woodland never got rich from barcodes, but he did get the 1992 National Medal of Technology from President George H.W. Bush. He still felt considerable pride in seeing his brainstorm almost every place he looked.
* THE AXIS BOMB FIZZLES: As far as the Axis bomb effort went, by this time it was all but going in reverse, with Les Groves making sure that the German effort was given a kick in the teeth. The British had drawn up plans to sabotage the Norsk Hydro heavy-water plant in Norway; Groves requested action almost immediately on taking charge of the Manhattan Project, and the British complied. An assault on 19 November 1942 involved the drop of 34 Norwegian commandos in two gliders and ended in disaster: both gliders crashed and the Germans shot all those who survived.
The British thought the matter over and decided to try again. On 16 February 1943, six Norwegian commandos were parachuted into Norway, to meet up with four other commandos who had been sent in earlier to make way for the failed assault in November. In a nighttime raid on 27:28 February, they infiltrated the plant's security perimeter, crept in through a drain, and planted charges to destroy the heavy-water production system. There were no casualties on either side in the operation; there was no way the plant would be producing heavy water again for a year.
In Japan, while physicist Yoshio Nishina worked on the atomic bomb for the Imperial Japanese Army, in July 1942 the Imperial Japanese Navy (IJN) set up a committee to secretly consider development of the atomic bomb. It deliberated into March 1943, to finally conclude it would take ten years for Japan to build an atomic bomb, and that nobody else was likely to be able to build one in the near future either. The committee disbanded, with the members going their separate ways, though a separate branch of the IJN continued to fund atomic bomb research at the University of Kyoto. The IJN knew little or nothing of Nishina's work for the IJA -- the two armed services had a case of interservice rivalry that defies belief, fighting like "dogs and monkeys", as the Japanese say, on almost every issue. Nishina's work had progressed to the point where he had ideas on how to perform isotope separation on an industrial scale -- at the very time Japan's war machine was starting to run out of resources.
* The fact of the matter was that the Axis was on the defensive. The Germans had suffered a major defeat at Stalingrad, with an entire German army encircled late in 1942 and wiped out a few months later. The Germans had been run out of Africa. The IJN had suffered a stinging defeat at Midway in June 1942, losing a good proportion of the service's vital aircraft carriers, and had been defeated in the battle for the island of Guadalcanal in the South Pacific. Now the Americans were poised to move against the island bases on the overextended perimeter of Japan's Pacific empire.
The brutality of the war was ramping up steadily. Intelligence was leaking out to the Allies about the mass exterminations of Jews and other "undesireables" in German death camps. The British had been conducting night bombing raids against Hitler's Reich; for want of better targeting accuracy, the raids deliberately and indiscriminately pounded entire cities. A series of massive raids in late July all but destroyed Hamburg, killing tens of thousands of civilians. In the Pacific, there were relatively few civilians in the way, but as if to compensate, the ground fighting was extremely vicious. The Japanese were not inclined to take prisoners, and a Japanese soldier usually preferred to kill himself up with a grenade rather than be taken prisoner himself; one would pretend to surrender and then blow up an American soldier along with himself. The Americans quickly got wise to this game and usually gunned down Japanese who appeared to be trying to surrender. When American bombers sank a Japanese troopship, they often came back and strafed the soldiers floundering in the water -- as if stepping on so many ants.
* While the Axis was giving up work on the atomic bomb, the Soviet Union was beginning to move forward on its own bomb development program. There had been some discussion among and lobbying by the Soviet physics roughly in parallel with similar efforts in the USA, and the authorities had become more interested in 1940 when fission-related work in the US and Britain simply disappeared from the scientific press. The work of high-profile nuclear physicists and chemists suddenly dried up, which all but convinced the suspicious Soviets that something big was going on.
Nothing much serious had been done when the invasion of the USSR in June 1941 suspended all work not immediately focused on the survival of the state. However, after the situation stabilized late in 1941, the Soviet government set up an advisory committee on atomic bomb development, including an ex-student of Rutherford's named Peter Kapitza and an influential physicist named Abram Joffe. The committee concluded that the Soviet Union needed to pursue atomic bomb research, and recommended that Igor Kurchatov, a big Siberian who was one of Joffe's star proteges, be assigned to head up the effort. Kurchatov was reluctant to take the job, believing that it would be wiser to focus on short-term research efforts in order to defeat the Germans, but he was persuaded to take charge.
* WORKING OUT THE DETAILS: While the struggle went on at the front lines, the physicists at Los Alamos focused on building the atomic bomb, wrestling with a seemingly endless list of theoretical and practical details. Enthusiasm was high; Oppenheimer later recalled Fermi telling him: "I believe your people actually want to make a bomb." Fermi found the idea distinctly appalling.
Work went ahead on the implosion bomb and gun-type bomb designs. The implosion bomb acquired the name of "Fat Man" because as it emerged it looked like an egg with box tailfins. Implosion was extremely tricky, requiring all the fissile segments to be blasted together with absolute precision. The technical boss on the design was Seth Neddermeyer, one of Oppenheimer's graduate students; the challenge was formidable, mocked by its critics as like trying to crush a beer can while keeping all the beer inside. Neddermeyer got help from John von Neumann, another of the Hungarian expatriate physicists, a brilliant theoretician who visited from Princeton.
The gun-type bomb had its own difficulties. Originally, the assumption was that it would have to be built around the barrel of an artillery piece, which resulted in a huge weapon, known as "Thin Man". As it turned out, since the gun was only going to be fired once, there was no need to build it like a real artillery piece. Gradually the design of the gun-type weapon converged on a more convenient device, which became known as "Little Boy".
In either case, the delivery system was going to be the Boeing B-29 Superfortress bomber -- the US Army Air Forces (USAAF) didn't have any other bomber big enough to handle either Fat Man or Little Boy. The four-engine B-29 was to be one of the most advanced aircraft of its era, capable of carrying a huge warload high, far, and fast. It was a high-priority project, funded at roughly the same level as the atomic bomb effort. For the moment, work on the Superfortress was not going smoothly -- the first prototype had caught on fire in February and crashed into a meat-packing plant in Seattle, killing all its crew and dozens of workers on the ground. Boeing engineers worked overtime trying to get the B-29 to fly right.
* The obvious critical path in the construction of an atomic bomb was to obtain fissile material. The appropriate "weapons grade" materials could be produced in principle by separating the traces of fissile uranium-235 from the much more common uranium-238, or by synthesizing fissile plutonium-239 from uranium-238 in what would eventually be known as a "breeder reactor".
While the Los Alamos site had been growing up out of the ground in New Mexico, under the overall direction of boundlessly energetic Les Groves, a facility at least as impressive had been put together in the mountains of east Tennessee to separate uranium-235 from uranium-238. The site was alongside the Clinch River and was given the cover name of the "Clinton Engineering Works", after a nearby town -- but it was more generally known as "Oak Ridge" after a local landmark. Construction had begun in the fall of 1942 and by 1 April 1943, the Oak Ridge site was ready for business.
There was a debate over the best way to separate uranium-235 from uranium-238. Ernest Lawrence preferred "electromagnetic separation" -- in essence, using a battery of modified mass spectrographs to do the job. The modified mass spectrographs were named "calutrons", after the University of California at Berkeley ("Cal-U"). It wasn't going to be an easy job, with Lawrence estimating that 2,000 calutrons would be needed to acquire a mass of uranium-235 adequate for a bomb in less than year. Others promoted separation by gaseous diffusion, and Lawrence didn't object: no industrial-scale separation method had been implemented to that time and there was no reason to bet the farm on any one scheme.
Les Groves hedged his bets and implemented both electromagnetic separation and gaseous diffusion systems. One of the problems with building the calutrons involved their electromagnets -- they required copper windings and copper was in short supply. The US Treasury Department came to the rescue, having offered to supply silver bullion to make wire, as long as the silver was given back in the end. The Army took up the offer, though when the officers involved told a Treasury official that thousands of tons of silver would be required, the official replied: "Colonel, in the Treasury we do not speak of tons of silver. Our unit is the troy ounce." The Army got the silver and Groves made sure it was meticulously accounted for.
Obtaining the metal for the windings turned out to be relatively straightforward, but the early calutrons shorted out easily, requiring a troublesome redesign. Building the gaseous diffusion system at Oak Ridge wasn't easy, either: the uranium hexafluoride gas was, as noted, hideously corrosive: the diffusion barrier had to be made of nickel and fabricated with a new process, while the seals in the piping had to be made of a new fluorine-based plastic that would eventually be known as "teflon". Any one stage of gaseous diffusion produced only a slight enrichment, so the diffusion system involved massive numbers of stages and a maze of piping.
The Oak Ridge plant ended up becoming a huge installation, with Ernest Lawrence being absolutely astounded by it during a visit in May 1943. However, by the end of 1943, fissile material was still not coming off the production line in any quantity. Groves wasn't happy, and when he wasn't happy nobody who worked for him was, either.
* Groves was not ignoring the option of breeding plutonium in a reactor, but there was no way to do that at Oak Ridge. A catastrophic failure of a breeder reactor would not only threaten the nearby city of Knoxville, but it would also shut down the rest of the Oak Ridge facility. An isolated site elsewhere was required.
It was found in the state of Washington, in the Northwest USA. Washington is stereotyped as damp and rainy, but that is only true of the western part of the state. The Cascade mountain range blocks much of the rainfall into the interior and central Washington is dry, an underpopulated sagebrush desert. The mighty Columbia river twists south the center of the state, finally turning westward to flow to the sea and establishing much of the border with the state of Oregon to the south.
The isolation of the area and the availability of the Columbia's water for cooling made the region an ideal site for a breeder reactor. A tract of ranchland near the little town of Hanford, on a kink in the Columbia just before it turned west, was duly purchased and construction begun immediately. A team under Eugene Wigner came up with a design for a water-cooled breeder reactor. It took some time to get work started -- unsurprisingly, there was a labor shortage and most available workers weren't keen on moving out to some barren desert where the summers were hot and sandstorms common. Those who did come found entertainments hard to come by in their free time, resulting in drunkenness, fights, and the occasional murder. Problems were dealt with, and by the summer of 1943 the facility was beginning to rise out of the desert.
* By that same summer, in the Soviet Union Igor Kurchatov's atomic bomb research team had moved from the halls of academia to a dedicated research facility on an abandoned farm on the Moscow River. There were only about twenty researchers at "Laboratory Number 2", and they were focused on preliminary studies. The USSR was not quite ready to move forward on full development of the atomic bomb.
* SZILARD PROTESTS: Les Groves not only had to deal with a long list of technical issues, he also had to ride herd on a gang of physicists, not all of whom were sufficiently submissive for his taste. The most significant case in point was Leo Szilard, who did not like the way atomic bomb development was under strictly military control and had not hesitated to make his concerns known. Later Groves would describe Szilard as: "The kind of man that any employer would have fired as a troublemaker."
This remark said more about Groves' arrogance than it said much about Szilard, with Groves casting Szilard in the role of a loose-cannon employee instead of the person who, more than any other one individual, was the father of America's atomic bomb program. In the fall of 1942, there had been a bureaucratic squabble between Groves and Szilard, leading to Groves toying with the idea of interning Szilard as an enemy alien. Compton interceded, smoothing over the trouble. Compton then passed up to Groves documents that Szilard had provided on his efforts to push atomic bomb research in 1939 and 1940, as well as Szilard's early attempts to shut down publication of nuclear research papers. Groves went quiet for the moment, but he was by no means reconciled to Szilard.
Szilard's pioneering work in atomic power also gave him some patents that he was able to use to make the authorities -- meaning Groves in particular -- uncomfortable. The patent issue did involve royalty payments, but Szilard mainly regarded it as a lever to ensure that his voice was heard. Groves found Szilard so annoying that, despite the fact that Szilard was Jewish, the general suspected the scientist was a Nazi spy. By the spring of 1943, Army Intelligence was tailing Szilard full-time. The intelligence people found their target amusing, an absent-minded sort, with an extensive social network of Jewish friends and many contacts with influential government officials. They reported there was absolutely no evidence that Szilard was anything but what he seemed to be.
Groves remained suspicious, repeatedly trying to pressure Szilard into signing a security pledge. Szilard repeatedly gave verbal assurances about his commitment to security and refused to sign. By the end of the year, the patent issue had been resolved, with the Army reimbursing Szilard for $15,416.60 for his unpaid work at Columbia in the time leading up to the establishment of the Manhattan Project. Szilard, however, still felt the need to make his views on the political implications of the atomic bomb known.
Szilard had been at the forefront of pushing the development of the atomic bomb, and remained at the forefront of raising concerns about its implications. There were good reasons for concern, since the bloody-mindedness of the war was continuing to spread, even among Los Alamos staff. In May 1943, following up some discussions among Met Lab staff, Enrico Fermi conducted a study on the possibility of dusting German food supplies with radioactive isotopes. The study concluding that the dusting could kill up to a half million Germans; Fermi was no longer as easily appalled as he had been. Oppenheimer conditionally gave his blessing to the idea, though it was really just a long-shot backup plan in case atomic bomb development went off track. It also raised the possibility that the Germans might try the same stunt. A number of US Army officers were sent to England with geiger counters and the appropriate training to provide a warning capability.
TO BE CONTINUED
* DISCOVERING DNA: While geneticists such as Haldane, Fisher, and Wright learned how genetics worked, biochemists worked to nail down its underlying mechanisms. By the 1920s, biochemists had effectively destroyed the idea that there was some magical "life force", undermining the "vitalist" mindset by showing that basic life processes were chemical in nature and followed chemical laws, successfully demonstrated many life processes in the test tube using biocatalysts known as "enzymes".
However, the biochemists were stumped by heredity. They had no idea of how heredity could be implemented with biochemical processes. In 1927, Hermann Muller, then working in Texas, provided a significant clue that heredity was in fact a biochemical process by showing that X-rays could cause mutations in the genes of the Drosophila melanogaster fruitfly. Later research showed that mutations could also be caused by high temperatures and certain chemicals. Obviously, such "mutagenic" influences affected the physical mechanisms controlling heredity -- whatever they might be -- just as they affected other biochemical mechanisms in the cell. Incidentally, Muller's work also allowed geneticists to extend their studies of fruitflies and other organisms through the creation of new traits and genes. They were no longer limited to the genes provided by an organism as it existed.
Despite this clue, the actual mechanisms of heredity remained mysterious. The next clue was found by the English biochemist Frederick Griffith (1879:1941), who in 1928 reported the results of his studies on Pneumoccocus bacteria. Griffith was able to obtain an extract from virulent Pneumoccoci that would turn benign strains of the bacteria virulent, and the descendants of these modified bacteria would continue to be virulent. Griffith discovered that he could kill bacteria with heat treatment and continue to obtain an extract that could instil virulence, long after the bacteria were dead.
In the mid-1930s, three researchers working at the Rockefeller Institute in New York -- Oswald Avery (1877:1955), Colin MacLeod (1909:1972), and Maclyn McCarty (1911:2005) began work to find the element in such extracts that instilled virulence in benign strains of bacteria. In 1944, they showed that "deoxyribonucleic acid (DNA)", a class of the "nucleic acids" found in cell nuclei, that had been extracted from virulent strains was entirely adequate to turn benign strains virulent. Selective destruction of DNA rendered the extracts ineffective in transmitting virulence, while selective destruction of proteins still left the extract capable of passing on virulence.
Their suggestion that DNA was the agent of heredity was controversial. DNA had long been known, and though its precise structure was not understood at that time, it was regarded as a simple long-chain molecule composed of four nitrogen-based molecular subunits called "nucleotides" that provided structural reinforcement for chromosomes. Complicated proteins seemed to offer many more possibilities as basic structures for the mechanisms of heredity than the simple and "boring" DNA. However, continued work showed that DNA did in fact encode genetic information. The most conclusive experiments were performed in 1952 by Alfred Hershey (1908:1997) and Martha Chase (1927:2003), who performed studies on "bacteriophages", or viruses that infect bacteria. Viruses were known to consist essentially of DNA and protein. Hershey and Chase showed that the bacteriophages injected their DNA into target bacteria, but left their protein components outside. The challenge remained as to how DNA actually worked, but by that time other biochemists were hot on the trail.
* THE MODERN SYNTHESIS: The work of Haldane, Fisher, and Wright in establishing neo-Darwinism was soon followed up by others. One of the first disciples was Theodosius Dobzhansky (1900:1975), a Ukrainian field naturalist and geneticist who had come to the USA in 1927 and signed up with John Hunt Morgan. Dobzhansky didn't much care for the untidy Columbia fly room, but when Morgan transferred to the California Institute of Technology in 1932, Dobzhansky followed him and found the land pleasant.
Dobzhansky was interested in the subject of genetic diversity. The general assumption of the time was that one member of a species was genetically very similar to another, a notion which was supported by Morgan's lab experiment with the Drosophila melanogaster fruitfly. After all, hadn't it proven difficult to obtain mutant variants? Dobzhansky wanted to test this idea, scouring the continent for samples of the related wild Drosophila pseudoobscura fruitfly and then examining their chromosomes under a microscope for distinctive markers. By modern standards, it was a primitive method, but later reexaminations of genetic diversity with vastly improved technology would show Dobzhansky was completely on the right track.
Using this approach, Dobzhansky determined that the variability of the wild fruitflies he caught was much greater than anyone had anticipated, and that variations were generally distinct to each population of flies. Dobzhansky was observing the branching tree of life observed by Darwin at the chromosomal level. Later examinations of the genetics of other species showed that Dobzhansky's wild fruitflies were much more the norm than the exception for organisms in terms of variability.
Although Dobzhansky was an excellent field biologist, he was also interested in theory, and found theoretical work by his contemporaries inspirational in helping piece together the implications of the genetic variability he had found in his wild fruitflies. He was absolutely taken with Wright's notion of an adaptive landscape -- Dobzhansky claimed he fell "in love" with it -- and in 1937, he published the landmark book GENETICS & THE ORIGIN OF SPECIES, the title of which explicitly married Mendel and Darwin.
Dobzhansky was in complete agreement with Wright's ideas about species that consisted of multiple isolated colonies of various sizes -- in fact, "it is very common in nature" -- and observed that these isolated subdivisions gave rise over generations into different races or varieties, and ultimately into different species. Although Dobzhansky was also initially convinced of the importance of genetic drift, in the light of further research by Fisher and others, he gradually became a much stricter selectionist.
In his work, Dobzhansky discussed in detail the impact of geographic or other factors that led to isolated populations, and also emphasized the "hidden variability" implicit in recessive genes. In particular, he demonstrated how heterozygous genes -- in which there were two different forms, or alleles, of a gene -- provided much more diversity and drive to evolutionary processes than homozygous genes -- in which the particular gene was invariant. It was such insights, as well as a popular writing style, that gave Dobzhansky stature. While crediting Haldane, Fisher, Wright, and others for key insights, Dobzhansky acknowledged that he was spreading the gospel: "What that book of mine ... did was, in a sense, to popularize this theory. Wright is very hard to read."
GENETICS & THE ORIGIN OF SPECIES didn't become a best-seller that took the public by storm, but it did make many key converts in the scientific community. In the USA, admirers included the German-born field zoologist Ernst Mayr (1904:2005), the paleontologist George Gaylord Simpson (1902:1984), and the plant geneticist G. Ledyard Stebbins JR.
In 1942 Mayr published SYSTEMATICS & THE ORIGIN OF SPECIES, which used Dobzhansky's work as a starting point. In this book, Mayr described species as simply inbreeding populations that were reproductively isolated from other groups, with issues of physical distinctions, such as morphology, regarded as irrelevant in that context. Mayr described the fragmentation of a population into several reproductively isolated groups, what he called "emergent species" with the term "adaptive radiation". He suggested what he called the "founder principle", which had a clear debt to the thinking of Sewall Wright: small isolated groups could undergo rapid evolution, since genes providing adaptive improvements didn't have to propagate through a large population, and if geographic or other barriers between the small population and a larger, less evolved population broke down, the improved variant might come into competition with the parent stock and quickly replace it.
Simpson, as a paleontologist, was familiar with the fossil record, which clearly identified a succession of forms. However, this progression of forms had proven misleading, since it gave the impression of straight-line progress to increasingly refined forms, suggesting non-Darwinian evolutionary mechanisms such as Lamarckism. Simpson was able to show that the fossil record was full of side branches and dead ends, just as Darwinism predicted it should be. The seeming straight-line progress was simply due to looking backwards over the line of evolution from its end and ignoring the branches. Simpson also noted that the fossil record was marked by confusing discontinuities in its history. In his 1944 book MODE & TEMPO IN EVOLUTION, Simpson interpreted this seemingly contradictory evidence by suggesting that evolutionary change was not a completely smooth process, instead being marked by rapid starts, long intervals of stabilities, and dead ends that vanished from the Earth in extinctions. The idea didn't catch on at the time, but it wouldn't be forgotten, either.
For his part, Stebbins extended the concepts of neo-Darwinism to the domain of plants, whose heredity tends to differ from that of animals, for example in their greater inclination to form polyploid hybrids, with duplicated sets of chromosomes. Despite the differences, Stebbins was able to show in his 1950 book VARIATION & EVOLUTION IN PLANTS that the same neo-Darwinian principles that applied to animal evolution applied to plant evolution.
* While the new generation of neo-Darwinists worked at the leading edge of evolutionary science, field biologists were reaching back to its beginnings for insights. One of Darwin's inspirations during his survey of the Galapagos had been the remarkable finches he had found there, varying according to size, beak, diet, and behavior, representing a branching of species from a common ancestral finch that somehow made its way from the South American mainland.
Darwin hadn't actually made too much of the finches, mentioning them in VOYAGE OF THE BEAGLE but saying little or nothing about them in THE ORIGIN OF SPECIES. Field biologists of the 1930s found them puzzling because of their extreme diversity, the belief being that natural selection would have trimmed off the proliferation of branches, involving populations of birds overlapping in form and range, into a few stable species. In 1935, the centennial of Darwin's visit to the Galapagos, the suggestion was floated that "Darwin's finches", as they were then named in his honor, deserved a closer examination in the field, where observations and breeding experiments could be performed.
Julian Huxley (1887:1975) -- Thomas Huxley's grandson, secretary of the Zoological Society of London, and a prominent British advocate of neo-Darwinism -- decided to back a shoestring expedition to the islands, obtaining modest funding for the effort and finding a young schoolteacher and amateur birdwatcher named David Lack (1910:1973) who was interested in the job. Lack left England in 1938 and went to the Galapagos on commercial steamer. He spent four months on his field study, hardly finding the arid, desolate, and impoverished islands any tropical paradise, which at least allowed him to focus on his work. Lack obtained detailed observations of the finches, determining that they constituted thirteen distinct species. He went to US and continued his studies using preserved specimens, working first in San Francisco and then in New York City.
In New York City, Lack roomed with Ernst Mayr, then the curator of the American Museum of Natural History. Not surprisingly, when Lack published his first paper on Darwin's finches in 1940, he was strongly influenced by neo-Darwinian ideas, leaning heavily on Mayr's notions of genetic drift and adaptive radiation to explain the diversity of the finches. However, the idea didn't sit comfortably with Lack, and when he published the book DARWIN'S FINCHES in 1947, he retained notions of adaptive radiation but made use of the notion of the "ecological niche", a notion that had been circulating among the biological community for about two decades.
An ecological niche can be thought of in a broad way as a "professional category" or "trade" applied to animals: ant-eater, plains herbivore, mole, large predator, and so on. When the first South American finches arrived on the Galapagos, as Lack had it, they found a domain full of empty ecological niches, allowing the descendants of the pioneering finches to expand into roles that would have been closed to them otherwise -- if an ecological niche had been occupied by another species, the finches would not have been able to compete in it. The fact that the finches occupied several relatively isolated islands in the Galapagos chain helped boost their diversification, but there were also overlapping species on each island. Competitive pressures gradually led to specialization among the various species.
Darwin's finches became such an icon of Darwinian evolution by natural selection in the 1950s that a false impression arose that Darwin himself had used them as one of the main supports of his argument. They have since been investigated in extreme detail, in particular by the husband-and-wife team of Peter and Rosemary Grant, who began a meticulous field study of the finches beginning in 1973 and still ongoing. The Grants were able to monitor the shift of the characteristics of finch populations in response to a multiyear drought, and their shift back to previous characteristics after the drought ended. The rate of shift as observed by the Grants suggested that if there were long-term changes in conditions on the islands, new species would emerge in only a few centuries.
* In any case, by the end of the 1950s, the work of Dobzhansky, Mayr, Simpson, Stebbins, and Lack had established a thoroughly renewed Darwinism, the "modern synthesis", grounded in a level of rigor and detail that would have astounded even the meticulous Charles Darwin. All serious traces of doubt over Darwinism in the scientific community disappeared, with few contesting Dobzhansky's simple claim that "nothing in biology makes sense except in the light of evolution." The science was not standing still, either; new insights had emerged that would take evolutionists several more steps forward.
TO BE CONTINUED
* Website additions for the month include:
Updated documents include:
New reviews include:
This last month's online blog entries include items on: railroad infrastructure, California road trip, resurgence of dengue fever, wind power in India, medical potential of symbiotic bacteria, personal rapid transport, contention over the North Pole's resources, Virgin America review, animal microtags, KGB in charge of Russia, cowbird protection racket, name-analysis software for security, tracing city population shifts through cellphones, fuzzy memories, and Canon Powershot camera.
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