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Enroute to other things I ran across an old Gulf R&D patent, US 3294685, titled “Organic compositions containing a metallo cyclopentadienyl”. Sifting through the description my eye caught the interesting content below:

July 1941. A test spray was prepared by dissolving 2.5 grams (3.2 percent) of iron dicyclopentadienyl in ml. of a typical household insecticide base oil. The tests made with this solution employed a dosage of IO-second discharge. An equilibrium :period of 15 seconds followed by an exposure period of 70 seconds, during which the mist was permitted to settle on adult house flies confined in a screen-covered dish, was employed in the tests. The results of the tests showed that of the flies which had been contacted with the base oil containing 3.2 percent by weight of iron dicyclopentadienyl, 53.6 percent were dead after 24 hours. Of theflies which were contacted with the base oil alone, only 13.0 percent were dead after 24 hours. Check flies which were confined for 24 hours without having been contacted with either the base oil or the base oil containing iron dicyclopentadienyl had a death rate of only 0.4 percent. The better than fifty percent mortality of the flies treated with the base oil containing iron dicyclopentadienyl is indicative of the insecticidal properties of naphthas containing a small amount of iron dicyclopentadienyl. Naturally, the amount of metallo cyclopentadienyl used in insecticidal compositions-will vary with the particular compound employed and also depends upon the particular insects for which the spray is intended. The amount of iron dicyclopentadienyl employed in insecticidal compositions intended for use on flies is between about 1.0 and 10.0 percent by weight.

Ya know, a greater than 50 % kill rate seems to be getting a bit sporty for the flies. The ol’ boys at Gulf were studying the suitability of a variety of ferrocene analogs for fuel additive application. What lead them to go from octane enhancement and smoke control to killing flies is not revealed in the patent.

Notice the nomenclature in the patent language. The word ferrocene is not mentioned. Looking at the timeline we see that the Gulf ‘685 patent was filed April 21, 1952, not long after the publication of this curious iron cyclopentadienyl compound by two groups, Kealy & Pauson on 12/15/51, and Miller, Tebboth, and Tremaine on 1/1/52. Though Pauson and Keely published first, an examination of the papers show that Miller, Tebboth, and Tremaine were first to submit- July 11, 1951 vs August 4, 1951 for Pauson and Kealy.

The day before Gulf filed the patent application, April 20, 1952, a groundbreaking paper by Wilkinson, Rosenblum, Whiting, and Woodward was published on the proposed structure of iron bis-cyclopentadienyl. It is reported that the name ferrocene was invented by Mark Whiting, a student of R.B. Woodward and coauthor of the 1952 paper in JACS. The name derives from the ferrous ion and the aromatic (“benzene”) nature of the cyclopentadienyl ligands.

The curious structure was proposed largely on the strength of a single C-H IR band at 3.25 μ. Since all of the C-H bonds appeared to be equivalent, the only structure compatible with the formula, charges and symmetry was the famous η5 (eta five) sandwich structure. Later the word metallocene finds use for this class of substances.

There is disagreement as to some of the details outlined above. An excellent article by Pierre Lazlo and Roald Hoffmann navigates some of the narrower channels in the history of ferrocene. It is well worth the read. Lazlo & Hoffmann suggest that Woodward is thought to have conceived the sandwich structure.

Ferrocene and derivatives would soon prove useful in many areas. A more obscure application is found in the field of rocket propellant additives and function as burn rate stabilizers. In fact, certain ferrocene derivatives appear on the US Munitions List, 22 CFR 121.1, Category V, (f)(4) Ferrocene Derivatives. A good overview of ferrocene and other metallocenes can be found in Wikipedia.

Circling back to the beginning of this piece, the patent application for Gulf ‘685 was filed 4/21/52, only 4 months after the publication on 12/15/51 of the Pauson & Kealy paper and two weeks later the Miller, et al., paper on 1/1/52. In the 4 months between Pauson & Kealy and the Gulf patent filing, two independent groups had published papers reporting the preparation of iron dicyclopentadienyl by different methods, a Harvard group had postulated a structure for the compound using IR data and a novel bonding type, and the Gulf R&D group had produced various analogues for testing as fuel additives. In this short time interval, the first organo-iron compound was taken from a literature source through industrial R&D and a patent application. As a premium, Gulf even determined that it had insecticidal properties. Much happened in a short time.

 


Wilkinson, Rosenblum, Whiting, and Woodward J. Am. Chem. Soc., 1952, 74 (8), pp 2125–2126. DOI: 10.1021/ja01128a527

Kealy and Pauson, Nature, 168, 1039 (1951). Received Aug. 7, 1951.  DOI: 10.1038/1681039b0

Miller, Tebboth, and Tremaine J. Chem. Soc., 1952,0, 632-635. Received July 11, 1951. DOI: 10.1039/JR9520000632

Laszlo P., Hoffmann R. ACIEE, 2000 Jan; 39(1):123-124.  DOI: 10.1002/(SICI)1521-3773(20000103)39:1<123::AID-ANIE123>3.0.CO;2-Z

Dear Rep. Lamar Smith,

Yer a smart feller there, Lamar. Ya have a BA from Yale and that JD from SMU. Ya passed the bar exam and started private practice in San Antone. In 11 years ya worked yer way up ta national ‘lected office.  It’s an accomplishment no matter how’ya look at it. And that America Invents Act piled on some mighty fine improvements ta the patentin’ process. That was good work there boy.

As chair of the House Committee on Science, Space and Tech-nology, ya been perty skeptical ’bout them snooty climate science boys with their jar-gon and their uppity attitudes actin’ all high’n mighty-like ’bout climate n’such. A good ole’ boy from the Hill Country ought ta be able to pick up on that fancy c’mputer modelin’, right?

I think that ya ought ta throw some of yer many talents inta climate modelin’ yerself. You’d be doin’ the scientific folks a favor. You’d roll up yer sleeves an’ dig in ta clean’n up that po-litically correct climate data. Darn tootin’ you would. I’m sure the folks at NOAA would give ya a desk er somethin’ ta do yer cipherin’.

Give it some thought, Lamar. Shouldn’t take more’n a few Saturday afternoons ta make a big dent innit. Don’tcha think? Keep yer head on a swivel.

Th’ Gausslin’

 

(Texican language services provided by Elroy)

 

 

 

 

Of the 1332 posts I have polluted cyberspace with, the most frequently visited is a post on the topic of neutron lethargy written in May of 2008. The post is titled Neutron Lethargy- This Weeks Obscure Dimensionless Quantity. My intent was to write about some of the obscure yet interesting factoids and concepts that I run into in my daily travails.

I’ve been drawn to nuclear topics since junior high school. Sometime in 8th grade I began to to build several scientific projects as described in the Scientific American column The Amateur Scientist written by C.L. Stong. Stong published a collection of articles in a book titled The Scientific American Book of Projects for the Amateur Scientist, 1960, Simon and Shuster. This book was (is) a treasure trove of information on how to assemble equipment for scientific investigation.

In jr high I spent some time trying to assemble an “Atom Smasher” (p 344). It was an evacuated glass tube with filament electron source a meter away from the positively charged target. The target was a 3 x 1/4 inch disk of aluminum with many perforations over which aluminum foil would serve to seal in the vacuum. The aluminum foil was to serve as a window through which electrons could collide with a sample on the exterior. Sadly the project eventually ended due to the lack of access to a McLeod gauge, bulk mercury, and a diffusion pump. The required Van de Graff generator was available for a few hundred dollars. The failure was perhaps fortuitous because even if I had managed to assemble the thing, I might have been exposed to x-rays during the accelerator’s operation.

Turning my attention to more feasible projects I did manage to do some biology experiments. The most interesting was growing protozoans from an infusion of grass and soil in standing water. After several days the water would turn cloudy and fetid. Using a decent Christmas microscope we were able to view a magical world of microorganisms scooting around in their herky-jerky manner. It was mesmerizing.

A glove box project afforded a place for growing microorganisms with petri dishes purchased at a hobby shop. I was able to grow mold and some blend of bacteria on Jello in the petri dishes, but the microscope didn’t have the resolution for bacteria. Since I had no interest in pathogens, the glove box was not really needed. But it looked cool.

By 10th grade I did manage to successfully build the cloud chamber project (p 307). Unfortunately I only witnessed stray cosmic rays and background radiation. As it turned out, the polonium 210 alpha source loaned to me by a physics teacher had long since decayed to inactivity. Building the chamber was a tremendous learning experience made possible through the use of the metal shop at school. It was of sheet metal construction with a dry ice and methanol coolant chamber built in. The actual chamber was made from  the bottom quarter of a Folgers coffee can cut and fitted with a glass viewing port and Plexiglass illumination ports. As I recall, the most problematic aspect of the construction was finding an adhesive that would not detach at dry ice temperature.

An electromagnet was built in an attempt to bend the path of the particles by a magnetic field, but was wholly inadequate for the job. Learned another lesson there too.

The book by Stong was something that lit up my curiosity and put a fire in the belly to explore. This was the beginning of what turned out to be life-long career in science. Strangely, the total lack of interest by the adults around me only strengthened my resolve to build and learn.

Guapo, AZ. The American Greenhouse Association (AGA) released a statement Friday in response to the Trump Administration’s denial that greenhouse warming is not based on established science. The spokesperson for the AGA, Mr. Harlan Stamen, announced that the greenhouse industry has begun a fundamental reexamination of the science behind the greenhouse effect. The AGA was one of many organizations meeting last week at their industry’s annual conference at Pultroon University.

Mr. Stamen, standing before a packed room of reporters, bluntly stated “we thought we understood how the greenhouse effect worked. Honestly, we thought that problem was solved. Then we hear from the new administration in Washington that as many as a few percent of scientists were unsure.” Stamen went on to say that greenhouse researchers were working feverishly to understand how certain substances, CO2 among them, in fact just do not absorb solar energy as believed. “Clearly”, Stamen allowed, “we have to figure this thing out. We have no clue how our greenhouses get warm in sunlight.”

The spokesperson for the White House Office of Inquisitions,  Olivia Gastly, Esq., released a statement saying that the Office is “aware of many individuals in Democrat science who think they understand these issues of climate- I mean, who knew it was so complicated-  but our belief .. our belief … is backed by many years of assurances by the very best people that using fossil fuels cannot possibly produce global warming.”

President 45 has chosen a cabinet, with senate confirmation, that outwardly seems chosen specifically to deconstruct the large scale structure of the federal government. This has come out in the open by admission from the likes of Steve Bannon, but serious dialog about the consequences of this has only just started.

If you step back a bit and think about what role the federal government has had in modern US culture, you might realize that the federal governmental superstructure has provided a framework and a shelter for many things citizens and businesses have come to rely on.

Some science oriented services the federal government has provided-

  • Funds for industrial expansion in 2 world wars
  • DARPA, which funds for the development of advanced military hardware, including aviation, communications, orbital platforms, electronics, robotics, computer technology, and more. All of this has spillover benefits to the nation at large.
  • A military establishment that countless young men and women joined that helped them build a career for life after enlistment
  • The GI bill post WWII credited with aiding the formation of the American middle class
  • The FAA regulates the operation of a large scale civilian aviation system, including organizing the airways, aviation safety, air traffic control
  • NIST, which provides for common weights and measures as well as the definition and standardization of many other units of measure for science and industry
  • CDC, which monitors and aids in the identification and containment of diseases
  • NOAA, which provides a large array of satellites and computer capacity for weather forecasting
  • EPA, that agency much maligned by pollution-generating industry, is charged with oversight of surface waters of all kinds as well as the purity of the air we breath.
  • The NIH which serves as an effective national resource for the advancement of medicine in research and in practice
  • The NSF has for many years funded basic scientific research, and in doing so provided many generations of scientists and engineers for industry and academics
  • NTSB is charged with investigating transportation accidents and promoting transportation safety
  • you get the picture …

I am not entirely sure what the slogan “Make America Great Again” really means. It is a brilliant piece of propaganda in the sense that it stirs the emotions of voters, but cannot be pinned down to any one meaning. The image of greatness is in the eye of the beholder.

When I think of this greatness business, my mind naturally goes to the source of our vast science and engineering prowess. The US evolved a unique and effective system of research and development.  The American university/government R&D machine has over many years provided breakthroughs in technology, but also it provides a constant supply of valuable scientific and engineering talent for any and all who need it.

Another benefit of our scientific establishment is the treasure trove of knowledge it leaves behind for posterity. Working in an R&D heavy manufacturing environment, I have at my finger tips the largest collection of international scientific references in the world. This is the CAS registry at the Chemical Abstracts Service and it is in fact national treasure.

I use this resource almost daily to uncover known technology and substances dating back to the late 19th century. A great resource to have because in business, you can’t afford to reinvent the wheel. And a lot of wheels have already been invented. Highly detailed information can be retrieved to provide the knowhow to solve problems encountered in industrial R&D today. Information that is in the public domain. Even better, because of the practice of peer-review, the information usually can be considered highly reliable.

Our government/university R&D complex is the goose that laid the golden egg. It is part of the engine of ingenuity that drives our economy.

Industry benefits from tremendously from a constant supply of talented engineering and scientific talent graduation from the best university research establishment in the world. It is this way in large part because of financial input from federal government funding agencies. Yes, there are monies available from private organizations. But I don’t think it compares in magnitude and breadth to funding from DoE, NSF, NIH, etc.

When I see that the present crew of republican elected officials and their appointees gunning for the large scale teardown of government agencies and reductions in force, I am naturally worried about the future of our education and R&D apparatus. I have trouble believing that the present congressional majority and the White House have the knowledge and intellectual bandwidth to comprehend the consequences of their actions.

This whole deconstruction of the federal government in favor of state control has the smell of a return to confederacy. Ask yourself how a confederate states of America would function when challenged by China or Russia militarily. How would the disunity by strong state control of resources respond in the case of an incremental land grab like the Russian takeover of Crimea. What if China takes over Taiwan and threatens hegemony of the Pacific?

The present political regime in DC threatens to do great harm to a civilization that used to be the envy of the world. Opportunity, wide open spaces, modernity were an attribute of a productive, unified nation. Do a majority of the citizens want what amounts to the libertarian dream of personal responsibility in the form of isolated bubbles of humanity? Does every aspect of our lives have to be a potential profit center for someone? Competition thrives with individual choice. But civilization requires cooperation. I vote for civilization.

 

 

EPA administrator Scott Pruitt has made clear by his comments that he knows little about science generally, let alone those areas that EPA is charged to oversee. If the Wikipedia site is to be believed, Pruitt’s education and career track in no way qualifies him to direct or make assertions on behalf of the EPA.

I would say that Pruitt does not have the credentials to speak authoritatively on the matter of climate science. This contention should be printed everywhere 24/7.

Plainly, he is the boss man of a wrecking crew for dismantling environmental protection.

 

 

A FLIR ONE ® infrared imaging attachment for my Android 6S cell phone arrived at my door the other day. The price was initially a bit high, $350, but had recently dropped to a more attractive price of $249, so I pulled the trigger. The online transaction on the FLIR website was seamless and the delivery time was less than one week. At the time the FLIR ONE® was offered on Amazon for the same price.

The unit has two imaging sensors arranged horizontally side-by-side and one centimeter apart: One optical sensor and one Lepton IR thermal imager detecting in the 8-14 micron wavelength range. According to Optics.org, the Lepton is an “uncooled long-wave infrared (LWIR) microbolometer focal plane array”. The FLIR has its own battery which must be charged separately. It will not energize from your phone’s battery.

FLIR image of our front entrance, April 1, 2016.

FLIR image of our front entrance, April 1, 2016.

The unit arrives nearly ready for plug and play. Before it can be operated the user must download an app from FLIR. This process went smoothly and in a short time I had the unit operating. The compact FLIR unit connects to the Android via the micro USB connector on the phone.

About the imaging. The FLIR ONE superimposes the IR image atop an optical image that consists primarily of edge lines defined through high contrast. This is a useful feature because it improves the image sharpness and helps set the context of the IR image. In a darkened space the optical image is lost and only the IR image will be visible (second image).  The IR image itself is relatively low resolution owing to the limited number of pixels from the IR detector. At close range a significant parallax effect occurs, appearing as shifted overlap of the optical and IR images.

The image above is an example of a false color image captured from the FLIR ONE. The shot of this north-facing door was taken during late afternoon on a sunny day in Colorado. The internal air temperature was ~68 °F and the outside air temp was ~35 °F in the shade. As is customary, the coolest temperatures are indicated in blue and warmer temperatures are indicated by a gradient from red to yellow to white. The IR sensor seems to saturate fairly easily, but the automatic exposure control will get a handle on the image, though not instantaneously. I have found that the best images are had by limiting the frame to avoid including overly IR-bright features. This allows the exposure control to bring out thermal subtleties in the image much as any auto exposure feature would in the optical range.

FLIR ONE image of a gas hot water heater under ordinary operating conditions

FLIR ONE image of a gas hot water heater under ordinary operating conditions

The second image shows a basement gas hot water heater and the hot water output line directed upwards to the floor joists. The hot water lines are insulated with closed cell polymer foam insulation from the local hardware store. The water heater has nothing more than the factory equipped insulation.

The FLIR ONE indicates infrared temperatures by way of false color images and spot temperature readings. But temperature readings from IR thermometry are not the whole story when it comes to understanding fugitive heat losses, radiative or otherwise.

An IR image shows surface temperatures based on assumptions on average emissivity and scaling through the Stefan-Boltzmann law. The amount of radiant energy emitted by a black body is defined by the Stefan-Boltzmann law. A plot is shown here. Emissivity is the quotient of emitted energy from a surface divided by that emitted by a black body radiator at the same temperature. Every surface has a characteristic emissivity based on its composition.  According to the linked emissivity table, polished aluminum has an emissivity of 0.095; concrete 0.95; mercury, 0.12; sanded spruce, 0.82; and white lacquer, 0.95. All these values are at 100 °C.

Home water heater. Aluminum foil on vertical hot water feed line

Home water heater. Aluminum foil on vertical hot water feed line

In the third photo, a 1 ft x 1 ft piece of aluminum foil was wrapped around a stretch of the insulated hot water feed line above the heater, as shown in the photo. The foil is in thermal contact with the foam insulation on the 3/4″ copper pipe. Hot water was run for a few minutes to draw heated water into the plumbing. Caution should be taken in that IR radiation does reflect off of surfaces which may lead to inaccurate conclusions about heat flow in the system in question. Above, the aluminum foil is reflecting some IR from another source. Up close and from another angle the foil appears much cooler than it is.

Plainly the emissivity of the highly heat conductive aluminum is different from the foam insulated pipe. The foil is in thermal contact with the foam and should be near the temperature of the foam surface, but the false color image suggests that the foil temperature is lower in temperature. Because of its much lower emissivity (ca. 10 % of foam) the foil only appears to be cooler. The foil is less radiant than the foam which has an emissivity of ~0.90.

Polished aluminum has high thermal conductivity but low IR emissivity. Foam, which has high IR emissivity (see images), is known for it’s insulating properties. And by that we mean, foam is a poor conductor of heat. What aluminum lacks in emissivity, it more than makes up for in conductivity. And while foam lacks in conductivity, it appears to be an efficient emitter of IR.

It is useful to mention the meaning of “insulation“. A material that conducts thermal power poorly can be said to have insulating properties. Thermal power (dq/dt) is the flow rate of thermal energy (q) per second. Thermal power is the rate of flow in Joules per second. For reference, one Joule per second is one Watt. The valuable attribute of a thermal insulator is that it can resist the quantity of power (Watts) flowing through a unit area such as a square meter. The amount of thermal power moving across a unit area, like a surface, is called heat flux and is in units of W/m^2.  It is common to express thermal resistance through a material by the R-value. An R-value is the ratio of the temperature drop (ΔT) across the insulating material to the heat flux through it, Q:  R = ΔT/Q.  So, as the heat flux gets smaller for a given ΔT, R grows larger in magnitude. In practical terms, a large R-value is desirable for insulation.

Looking at the radiant stretch of emissive insulated pipe rising from the water heater, we might initially guess that the IR image shows the whole thermal picture. But really, this guess is muddied by details. A warm pipe will be radiating energy as well as losing heat by conduction to whatever it is in contact with and by air convection.

IR radiation thermometry is useful when measuring a surface temperature is not practical. Accuracy, however, will depend on the emissivity of the surfaces of interest. The FLIR ONE is an economical imaging device for capturing IR images of large areas. The spot temperature feature is useful for recording the temperature of desired objects. Image files are easily downloaded from the phone and manipulated as jpeg files. Users will find many good applications for this affordable and easy to use IR imaging system.

Easy and cheap is great, but it is advisable for those wanting to do commercial work with IR thermography to take credible coursework and obtain some credentials. There are a few subtleties to thermography and it is best to be a little overqualified than not. Thermography courses can be found on the internet.

 

 

I have spent some time researching basic magnesium chemistry. Not anything synthetic but more safety and thermochemically related. I am not able to give a lot of particulars motivating the study, but I can say that one should consider that nitrogen over activated magnesium may not be as innocent as you think. While lithium is widely known to react with nitrogen gas to form a passivating nitride layer, the reaction of dinitrogen with magnesium is rarely encountered.

Activated magnesium residues from a Grignard or other magnesium metallation reaction may self-heat to incandescence under a nitrogen atmosphere in the right circumstances. Activated residues left isolated on the reactor wall or other features in a nitrogen blanketed reactor during an aqueous quenching procedure may self-heat to incandescence. In the presence of reactive gas-phase components like water vapor in nitrogen, activated metals can self-heat over an induction period of minutes to hours or longer.

Many metals, including magnesium and aluminum, can be rendered kinetically stable to air or humidity by the formation of a protective oxide layer. Once heated to some onset temperature by a low activation reaction, penetration of the protective layer by reactive gas composition can occur, leading to an exothermic reaction.

Performing a “kill reaction” or a quench of a reactive metal at the bench or at scale is always problematic and requires the skill and close attention of the process chemists and operators. I guess what I’d like to pass on is that nitrogen is not an innocent spectator in the presence of finely divided, activated magnesium. Humid nitrogen can support a combustion reaction to produce nitrided magnesium once preheated to an onset temperature.

If you mean to kill any reactive residues, it is important to apply the quenching agent in such a manner that the heat generated can be readily absorbed in the quenching medium itself. A good example of a quenching agent is water. Often a reactive must be killed slowly due to gas generation or some particular. Adding a quenching agent to a solution or slurry by slow feed or titration may be your best bet. If you have another vessel available, a feed to a chilled quenching agent will also work.  Dribs and drabs of water on a neat reactive material will lead to hotspots that may be incendive.

The news feeds are piping articles across the internets about Americans and their views on matters of science. Of particular interest is the finding that 51 % of respondents expressed a lack of confidence in matters of the big bang and cosmic origins and age. Predictably, scientific models of human origins and evolutionary science also elicited a considerable lack of confidence.

As the linked article in The Atlantic suggests, there is nothing new in America about ignorance of science and its panoply of theories, models, images and data. I’ve come to believe that wide spread ignorance of science may be contracting a bit. Some folks might be a little less refractory to science if gently brought into the discussion.  It is especially evident when you engage someone in conversation about the concepts with which they might anonymously criticize in a survey. Often if you can get a person past a key mechanistic concept, their dogmatic view of things may soften.

Scientists tend to look at new things analytically and with skepticism. Others may have a devotional world view. The devotional approach is the programming language of faith in and preservation of doctrines. For the scientist, the goal is to strip doctrines to their bare mathematical essence- a single equation that describes the relationships between variables and fundamental constants. If something is observed, measurements can be taken.

Molecular medicine and microbiology unavoidably force one to come face to face with the plasticity of DNA and the short term variability of genetic change. Resistance to drugs or the spread of BT or glyphosate resistant traits into insect and weed populations are a great entry point for talking about molecular evolution. It also allows one to get away from the troublesome paradigm of Darwin, whose work carries religious baggage for many. Irrespective of what Darwin wrote, modern molecular biologists would have eventually postulated and substantiated evolution from the molecule up, as opposed to the Finch down. The Darwin model of evolution has become tired and a little worn. We really should be giving more credit to molecular biology for advances in the understanding of genetic change.

I think those who have devoted their lives to understanding science tend to forget the tremendous expenditure of time and effort that goes into a deep  and quantitative understanding of nature.  My experience in teaching and in public outreach in science has been that a great many people are willing to be entertained by presentations on extrema, that is, the biggest, the most powerful, the most dangerous, the most poisonous, etc. Folks like to hear about extreme phenomena and scientists are only too happy to talk about the dangers of black holes or volcanoes or ferocious animals.  One can spend an evening talking about such things to a general audience and go home with the impression that the public eats this stuff up.

However, if you closely converse with your audience, you may find in many that their interest is genuine but superficial. They are entertained by the gosh-wow aspects of astronomy, but are unwilling to commit the time and effort to enough study to be competent in a topic. They often only want to see the moon through a large telescope and then go home. This is just human nature and science folk cannot be offended by the slender attention span of the public. Learning science requires a good deal of work and focus. That a large slice of the population is suspicious of the big bang theory suggests that said population has not made the time and energy commitment to learning the science.

This is an excerpt from a writing project I’m working on.

The impulse to find and extract gold and silver was one of the drivers of 19th century westward expansion in North America.  The discovery of gold in a California stream bed in 1849 and the subsequent discovery of gold and silver in other territories eastward to Pikes Peak and the Black Hills resulted in waves of migration of prospectors, merchants, investors, and swindlers from all directions, including Europe.

The staking of mineral claims in the American west by people who were engaged in the extraction of mineral wealth lead to an inevitable avalanche of settlers interested in tapping some of the wealth of the miners themselves. The open territory created a void that was filled by industrialists, merchants, government, and perhaps most importantly, the railroad. Miners needed supplies and their ore concentrates required transportation and beneficiation.

As claims were made on valuable mineral deposits, the outline of the geographical distribution of mineral value in a region eventually defined what came to be known as a district. The expansion of the railroad, sweetened by land grants, added permanence to the settlement of many regions around and en route to the mining districts.  The simple logistical requirement of frequent stops to fill the steam locomotive with water lead to the establishment of towns along the railway. This expanding transportation network, along with liberal access to land, lead to settlement by farmers and ranchers who then created a demand for goods exported from long distances by rail.

The history of man’s fascination with gold and other metals is well documented and there is no need to reiterate that saga in the present work. The mania for gold and silver in the west is legendary. Indeed, clues to the history of gold and silver mining in the American west are quite apparent even to the casual observer today. A drive to Cripple Creek or Central City in Colorado will take the motorist past a great many long abandoned mine dumps, prospect holes, adits, and antiquated mineshaft head works. These quiet features of the landscape mark the location of what was in times past a great and bustling industry.

Throughout the American west today there are many “tourist mines” and mining museums operated by individuals and organizations who recognize the importance of keeping this part of our cultural heritage alive. Through their efforts, visitors can view 19th century mining technology on site and experience the dark and eerily silent realm of the miner. Visitors can see for themselves the intense and sustained effort required in hard rock mining and the occupational hazards miners were exposed to.

The tourist mines and museums often focus on the activity of mining itself as well as the specialized equipment needed to blast the rock and muck it out of the mine. This is only natural. The gold and silver rushes left behind a large number of artifacts. These items are of general interest to all.

The technology that is often glossed over relates the matter of getting the pay out of the pay dirt. Indeed, this is a central challenge to gold and silver extraction. Once the streams have been depleted of placer gold and the vein or lode has been discovered somewhere up the mountainside, the business of extracting gold or silver from hard rock becomes technically much more challenging and capital intensive.

The panning and sluicing of placer or alluvial gold, while labor intensive, is conceptually easy to grasp. High density gold particles can be transported by suspension in a water slurry of the water is moving sufficiently fast. Gold particles will tend to settle at low points in a crevice or a gold pan where the stream velocity slows. A gold pan or the bend in a stream for that matter will have a flow gradient that will tend to collect the gold particles where the stream velocity slows.  A sluice or a Wilfley table are just devices designed to trip laminar fluid flow by inducing turbulence to encourage the denser gold particles to settle. Riffles or channels serve to concentrate the gold particles.

While gravity and clever tricks with fluid flow can be used to collect placer gold, isolating gold or silver from a hard rock ore body is quite a different challenge.  Gold and silver may exist in reduced form within the ore. They may also be found alloyed with one another or otherwise combined with other heavy elements. While gold tends to be inert even under oxygenated conditions near the surface, silver is subject to more facile oxidation and may be found in ionic form with several anionic species. Thus technology for the isolation of gold may not serve as an exact template for silver extraction and isolation.

Gold or silver may exist in the metallic form as bodies visible to the naked eye within the solid rock. Or they may be dispersed in microscopic elemental form throughout the ore body. Gold ore may be rich in elements that complicate its isolation even though the gold is in reduced form.  Silver ore is commonly found in ionic form and with numerous ionic base metals present.

Lode gold or lode silver, that is, gold and silver found dispersed in an ore body, were subject to considerable variation in mineral composition. As a result, differences in isolation techniques and process economics arose among the various operations.

In the 19th century a considerable body of chemical knowledge evolved as the gold and silver rushes progressed. This chemical knowledge was put into practice largely through the efforts of mining engineers.  It was not uncommon for the mining engineer to conceive of what today would be considered a process chemistry change, draw up plans, press the ownership for funding, and put the change into operation.

Twenty-first century chemists may recognize much of the nomenclature from this period as well as the intended inorganic transformations. However, the older literature is filled with obsolete nomenclature or that which is confined to the mining industry.  What should be apparent to the observant reader is the level of sophistication possessed by 19th century metallurgists and engineers in what chemists today might refer to as the “workup”.  That is, the series of isolation steps used to remove undesired components to afford a reasonably clean metal product. Mining engineers refer to this as beneficiation or as extractive metallurgy. Beneficiation of lode gold and lode silver involved chemical transformation in batch or continuous processing.

The story of the development of extractive metallurgy is in part the story of redox chemistry on complex compositions like rock. In the mid 16th century Europe, key individuals like Biringuccio, Agricola, and Ercker began to capture mining and extractive metallurgical technology in print. Vannoccio Biringuccio (1480-1539) published his De la pirotechnia in 1540, detailing economical methods of metallurgy and assaying. In 1556, the work of Georg Bauer (“Agricola”, 1494-1555) was published posthumously. His De re metallica is regarded as a classic of metallurgy. Agricola’s book describes the practical issues related to mining, smelting, and assay work and is illustrated with remarkable woodcuts.

By the year 1520, do-it-yourself books like Ein nützlich Bergbüchlein and Probierbüchlein were beginning to appear in Europe describing basic mining and metallurgy techniques.[1] By this time methods of cupellation and the separation of gold and silver were committed to print.

Cupellation is an assay technique wherein crucibles made of bone ash were used to fire prepared gold ore samples with an oxidizer, affording base metal oxides which then separated from the gold and absorbed into the crucible to afford an isolated button of gold.


[1] Aaron J. Ihde, The Development of Modern Chemistry, 1964, pp 22-24; Dover Reprint 1984, QD11.I44, ISBN 0-486-64235-6.

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