The reconstruction of Magdeburg brings to mind issues in population density. Although relatively large cities existed in 1634 in OTL, none of them qualifies as a really modern city, as the up-timers would recognize them. The up-timers will cause an unparalleled population density explosion, based on the technologies and the social systems that were developed in the late nineteenth and in the twentieth centuries to handle the growth of the megalopolis.

None of the large cities of Europe or Asia qualified as metropolitan until nearly the end of the nineteenth century. Why? To handle large scale urban populations of the density of even a twenty-first-century Hamburg, you require a combination of the effects of the development of five things. You need the germ theory of disease and epidemiology, centrifugal pumps and the associated high pressure piping, electricity, and the modern safety elevator. What, you say? They had pumps, they had running water . . . All that's true, but this is a synergism. You need all of them to make a modern metropolis work.

So, what's a large, modern city? Here are the 2007 top five:

By Population

1 Tokyo/Yokohama Japan 33,200,000

2 New York Metro USA 17,800,000

3 Sao Paulo Brazil 17,700,000

4 Seoul/Inchon South Korea 17,500,000

5 Mexico City Mexico 17,400,000

Now, contrast this with what passed for a large city in the seventeenth century. The two largest cities in the world were Beijing and Constantinople, both with roughly 700,000 people. Edo, Japan, the core of modern Tokyo, had roughly 575,000 people. London and Paris were the largest cities in Europe, with close to a half million people each, while Naples had 300,000 and Amsterdam had 200,000.

In order to cram 33 million souls into 6,993 square kilometers, as Tokyo does, or close to 18 million into 8,683 square kilometers, you have to build high. Tokyo and New York are both in the top five of cities with the most skyscrapers.


You need a clear understanding of the germ theory of disease, especially for waterborne illnesses. It is arguable whether cholera existed in northern Germany in 1630 but it would not be long before it came there. It was the understanding of how cholera is transmitted that created the discipline of epidemiology, and led directly to the concept of making drinking water safe. This didn't happen until Dr. John Snow, who appears to have singlehandedly created the modern science of epidemiology, and his friend, the Rev. Henry Whitehead, determined the importance of the Broad Street Pump to the London Cholera Epidemic of 1854. Granted, Whitehead and Snow didn't understand the germ theory of disease, but their work pointed to it and it provided the final key in the lock of safety from disease.

At the time, London had the highest population density on record, more than two million people in a ten mile circumference. But what was true for London in 1854 had been true for every large population center in history.

Cities had sewers. Cities had water companies. Some cities had running water in some wealthier dwellings, and some even had flush toilets. What they did not have was a clear understanding of how to ensure that the water supply was drinkable, because they didn't understand the link between water-borne bacteria and disease.

Cities generally obtained their water supplies from either surface water (rivers, lakes, and stormwater catchments) or ground water, or a combination of the two. Water intakes were, as often as not, downstream from wastewater discharges since there was no understanding of water-borne pathogens. Groundwater supplies tended to be shallow subsurface wells, since drilling deep water wells was not yet technically practical, and would not be until deep drilling techniques became powered by steam. These “groundwater supplies” were actually easily contaminated by surface pollution, as the story of the Broad Street Pump describes.

Getting the water from its sources to the population was not trivial, either. Modern cities are built over a grid of water pipes that is divided into pressure zones. Pumps and elevated storage are used to maintain relatively constant pressure in all the pipes in each zone. In some cases, it required the development of cast iron pipe and high pressure pumps to produce high enough pressure to feed all the parts of the grid.

Getting wastewater away from its sources was also non-trivial. Ranging from simply putting the contents of the chamberpot in the basement (England) to opening the window and splashing it out into the street (in France and Scotland “gardy-loo” or garde l'eau was the traditional cry given just before the toss) to saving it for collection and re-sale to the dyers and tanners (Germany, the Low Countries, and Italy) there was virtually no organized attempt to collect and remove wastewater, and treat it before it returned to the surface water and ground water supplies.

The 1632verse is different. Grantville appeared, complete with physicians, nurses, medicines, textbooks, and a public health praxis that the Early Modern Europeans could see working.

Grantville's largest impact in its first few years of existence in Thuringia will be the dissemination of modern public health practices—not modern medicine. Simple adherence to the basics of modern public health as the up-timers knew them (especially regularly washing hands with soap) will have a huge impact on reducing infant mortality, lengthening lifespan, and reducing death from disease. And, since no good deed goes unpunished, this will, of course, lead directly to a population explosion.

More and more people, living in close proximity, eating and excreting . . . a breeding ground for cholera, typhoid, and other water borne diseases.


The second thing you need is a practical means of disinfection for both water and wastewater. This means: easy to produce, understand, and maintain. In addition, you need to have the ability to make sure that any given amount of water is drinkable and safe.

This didn't occur in OTL until after John Snow and Henry Whitehead proved that cholera (and by extension, other diseases) was caused by contamination of water by human feces. Shortly afterward, Semmelweis, Pasteur, Lister and Koch proved that the microorganisms first being identified in the seventeenth century by microbiologists like van Leewenhoeck were the proximate cause of diseases like cholera.

Once we knew what caused cholera and typhoid, it was a quick step to find a means to destroy the enemy bacteria.

In 1913, a typhoid epidemic struck Northern New Jersey, and the source was identified as a stream feeding into a reservoir in Boonton that was the water supply for Jersey City. Charles Wallace and Martin Tiernan finally found a way to inject measured amounts of chlorine gas into the water in a repeatable way, providing the first reliable means of disinfection of a public water supply. Chlorine, in either gaseous form or in the form of sodium or calcium hypochlorite, had been tried previously, but too little chlorine has no effect, and too much chlorine in the water produces diarrhea and vomiting in victims. Wallace and Tiernan made it possible to accurately meter chlorine into the water supply. Why chlorine? Chlorine carries a residual which means that you can be sure that the water in which chlorine is present is disinfected. And this residual is easy to measure.

Grantville came through the Ring of Fire with three working disinfection systems: the power plant's cooling water system, the city water treatment plant, and the city wastewater treatment plant. The engineering library at the water plant and the public works department and the wastewater treatment plant had multiple copies of Standard Methods for the Examination of Water and Wastewater, the treatment and testing bible of late-twentieth-century water treatment as well as copies of The Manual of Practice for the Disinfection of Wastewater and Chlorination of Water. So they understand how to do it, and have working systems to pattern from.

It isn't enough to understand epidemiology, you also have to have the technology and tools to do something with it.

A brief mention must be made of the social response to the new theory of epidemiology and disease. Laws were passed ensuring that public urination and defecation were forbidden. Renewed importance was given to bathing and general cleanliness, especially after Nightingale, Lister and Koch proved that disinfection lowered mortality rates in hospitals by orders of magnitude. As it will in the 1632verse, simply making the washing of hands a socially-important behavior will do more to increase population growth than almost any other thing.

Centrifugal Pumps

There are two reasons why buildings in large cities throughout history have been low rises. One is the fact that climbing stairs is a real pain after about five or six floors, and the other is that it just isn't possible to use a positive displacement pump (think the well pump from the Old West farmyard, or the infamous Broad Street Pump) to pump water higher than about twenty-two feet in the air. Buildings with floors higher than this had no water on the upper floors, and were unpleasant to live in, as well as being serious fire hazards, since the fire department couldn't get water up there either, if there even was a fire department.

Luckily, in the middle-seventeenth century, OTL, inventors in England, Holland and Germany came up with a mechanism for moving large amounts of water that could pump very high pressures. It was called the centrifugal pump.

This kind of pump has a rotor with curved blades on a solid backplane. This is called an impeller. The impeller sits inside a narrow casing inline with the casing's inlet and outlet. The outlet of the casing is smaller than the inlet. The impeller turns at a relatively high rate of speed (needs an engine or motor to do that) and causes a slight suction that pulls water into the casing chamber or “pump bowl” and forces the water out the outlet at a high rate of speed and pressure. A refinement of the principle, the turbine pump, has straight vanes, and both impeller and turbine pumps can be staged, with the output of one chamber or bowl feeding the next, and so on. Deep well turbine pumps are often designed with many multiple stages. Six to ten stages are common for a deep water well.

Depending on the design of the centrifugal pump, water can be pumped at very high pressures. An outlet pressure of 100 psi, for example, would allow the water to rise 220 feet in the air. This might serve a building approximately twenty-two stories tall.

The earliest centrifugal pumps were made of wrought iron, with wooden bearings and in some cases, wooden shafts. Seventeenth-century metallurgy had not yet produced the high pressure piping necessary. Cast iron pipe for larger diameters than about two inches, brass and copper for smaller diameters, needed to be developed in order to fully utilize the kinds of pressures centrifugal pumps could produce. Metal tanks that could be pressurized and used as surge, or hydropneumatic tanks also needed high pressure metallurgy.

Grantville brought dozens of working centrifugal pumps to the 1632verse. Reverse engineering them will be nearly instantaneous, especially since the principle of centrifugal pumping was already beginning to be used.

Until the metallurgy of the 1632verse catches up to the twentieth century, we'll have to be careful of building pumps that are too high pressure for the pipe they are connected to. In OTL, what early modern “skyscrapers” did was to position water tanks in stages, and pump water from a lower tank into a higher one, until finally the water reached the tank mounted on the building's roof. Water pressure was maintained in this tank, to feed all the taps in the building. The citizens of Magdeburg and other large cities will do the same thing.

The Safety Elevator

One of the first things that happens in an urban population explosion is that it becomes much more efficient to build up, rather than out. Cities as old as Republican Rome had relatively tall (perhaps as high as seven stories) buildings, but the upper floors were undesirable, because there was no water supply, no easy way to get water there, and no way to bring your stuff up, except by the stairs.

Elevators have been known and used since ancient times, but they were clumsy, slow, hard to power, and extremely unsafe. Elisha Otis' patent 31,128 was the other thing that made high rise domiciles possible. In 1854, his invention of the elevator safety brake was revealed at the Crystal Palace Exposition in New York. The brake made it possible to stop an elevator in just a few inches if the lifting cables broke. High pressure pipe and high pressure-capable steel vessels made high pressure steam engines practical, which in turn made cable operated elevators with safety brakes a simple means of moving people and goods in a vertical direction. This made easy access to upper floors on a high rise building practical.

Here again, the 1632verse will differ markedly from the OTL. They start with working safety elevators, and an understanding of how they work, and why they are necessary.

One of the up-timers, Howell Tillman, and his apprentice and partner, Laura Beth Trimble, has started an elevator repair, maintenance, and design firm called Howard Tillman and Associates. Duplicating Grantville's few modern elevators will be in substantial demand as soon as Magdeburg finds that it is necessary to go up rather than out as population grows.

Early modern elevators also only went up a few floors. Then you had to get off at an elevator landing and take another elevator to higher floors. This was because of the weight of the cable needed to make an elevator that would go more than six or eight floors. As 1632verse technology improves the manufacture of woven wire cable, elevator technology will also improve, and elevators will be used for higher and higher buildings.

Smaller and easier to run electric motors will also improve the elevator. If you need a steam powered donkey engine in the basement to run the elevator, you can't run it up very many floors. But if the motor is small enough in size and weight that it could be mounted on the roof, or on an intermediate floor, the possibilities for expansion are endless.

Why were electric motors necessary? Once you install an electric motor, and give it a power supply and turn it on, it will continue to operate unattended until the power supply is interrupted, either by power failure, or when you turn the motor off. It has a very small footprint per unit energy produced. Contrast this with a small high pressure steam engine, of the kind known as a “donkey engine.” This engine requires a source of water, a way to vent steam, a smokestack, a source of fuel (usually coal) which must have storage, replenishment, and cleanup, and an engineer or suite of engineers, who attend the engine during its operational life.

The other important development that will make elevators useful in handling high density populations is signaling. It is necessary to let the elevator operator (early elevators would have human operators, instead of automatic controls) know what floor needs the elevator. Simple electromechanical signals are only available if the building has electric power.


The final piece in our synergistic puzzle was not just the discovery of electricity, but the ability to deliver it in a grid pattern anywhere people wanted to use it to do work. Widespread availability of cheap power in the form of electricity is the engine that powers the modern metropolis.

Electricity makes practical things that twentieth century OTL citizens take for granted: fresh meat, fresh vegetables, frozen foods, climate control in buildings, effective and safe lighting in buildings and streets, and powers the communications media from the telegraph and telephone to HDTV and the Internet.

A significant population limiter that electricity and the development of powered refrigeration eliminated was the need for the city to be located within one day's shipping time from the sources of fresh food. Meat, poultry, milk, butter, eggs, greens, all had to be produced in the immediate outskirts of the city. This limited the geographical area into which the population could expand, while the lack of electricity also limited the vertical geographic expansion as well. The lack of electricity meant that the largest non-electrified city in history, nineteenth-century London, had a population of around 2 million at most.

Electricity makes lighting, heating, powering elevators and pumps practical in high volume. This eliminates the height restrictions on population expansion. Electricity allows both for local storage of refrigerated goods, but also the shipping of refrigerated goods in trucks and railcars.

In addition, electrical controls and signaling are much more efficient and easy to produce and maintain than mechanical or pneumatic controls and signal lines. The development of electrically powered motors, switches, relays, and other controls made the development of the modern factory practical, which in turn allowed for more employment in the city, which, in its turn, encouraged population growth.

Like the OTL, the form power distribution will likely take will be AC or alternating current. As nineteenth-century utilities found, distributing alternating current is easier, simpler, cheaper than trying to distribute DC, direct current, power. Why not build local building generators? Why centralize the production of generated electricity? First, if each building has its own power generator, it must also have in multiplicate the logistics necessary for serving that generator, including fuel, fuel storage, fuel delivery, operations and maintenance and engineering crews, and the generator will take up space that as population density grows, will become more expensive. Contrast this with a central power generating station which only needs a single logistics train, and which can, in the case of hydroelectric generating stations, be located considerable distances away from the city itself.

One of the things to be explored in the 1632verse is whether DC power will be used within highrise buildings, or whether, as in the OTL, AC will be served directly to the appliance.

These are the five things, working together, that the 1632verse has from the very beginning, that the OTL took from 1600 to 1920 to develop. Working together, they will permit the rise of the modern urban metropolis in 1634, rather than waiting until 1900.

Sources:(all of these books, with the exception of Johnson's, went through the Ring of Fire with Grantville)

Johnson, Steven. The Ghost Map: The Story of London's Most Terrifying Epidemic – and How It Changed Science, Cities, and the Modern World, Riverhead Books, The Penguin Group (USA), 2006. ISBN: 1594489254

White, George Clifford. The Handbook of Chlorination and Alternate Disinfectants, Wiley-Interscience, 4th edition, 1998. ISBN: 0471292079

Macaulay, David. The Way Things Work, Houghton-Mifflin, 1982

Lobanoff, V. S. and Ross, Robert. Centrifugal Pumps: Design and Application 2nd Edition, Gulf Professional Publishing, 1992

Avallone, Eugene A. and Baumeister, Theodore. Marks Standard Handbook for Mechanical Engineers 10th Edition, McGraw-Hill, 1996