Monday, February 20, 2017

George Goodwin: Joseph Priestley, a towering figure in a special relationship with America’s founding father

The Joseph Priestley statue in Birstall.

[Editor's note:  The following article by George Goodwin appeared in the Yorkshire Post on Friday, 17 February, 2017. It is reprinted here, with permission,  Johnston Press plc. Registered in Scotland no. SC015382 Registered Office:Orchard Brae House, 30 Queensferry Road, Edinburgh EH4 2HS. All rights reserved.]

Well positioned in the Market Place of the West Yorkshire village of Birstall is a statue to Joseph Priestley. This 1912 memorial was funded by public subscription and the slightly larger-than-life bronze figure is a fine piece of sculpture by Frances Darlington, the Headingley-born and Harrogate-based sculptor who was trained at the Slade School of Art. 

The lettering on the statue’s square base of grey granite notes that Priestley was born at Fieldhead, Birstall, in 1733, and describes him as the ‘discoverer of oxygen’. It is a fine monument to Birstall’s most famous son and it is true that he was the first to isolate oxygen, along with six other gases. This discovery was of fundamental consequence, yet to limit Priestley’s importance to that one achievement would be to similarly summarise Benjamin Franklin as merely the inventor of the lightning conductor. 

It is an apt comparison, because the two men were major figures of the British Enlightenment. They were great scientists, both winning the Royal Society’s Copley Medal, the 18th century equivalent of the Nobel Prize. They also became very close friends and this year marks the 250th anniversary of the publication of Priestley’s The History and Present State of Electricity, with Original Experiments

It was while undertaking his research for the book that Priestley was introduced to Franklin, the greatest living authority on electricity. Franklin lived in London from 1757 right up to March 1775, with the exception of just a short 18-month break back in his home town of Philadelphia. He was ostensibly here as a political representative of the Assembly of Pennsylvania, but was also celebrated as a natural philosopher at a time when the politically dominant British aristocracy were in the grip of a scientific craze. Franklin was not only the most famous American in Britain, with David Hume calling him “America’s first great man of letters”, but was esteemed across Europe, with Immanuel Kant describing him as “the Prometheus of Modern Times”. 

Between 1767 and 1773 Priestley was the dissenting church minister at Mill Hill Chapel in Leeds, and another statue of him still overlooks the chapel from City Square. During this time, the friendship between Priestley and Franklin was strengthened by their regular exchange of letters ranging across science, philosophy and politics. In 1771, Franklin went on holiday in the North of England with a group of fellow spirits that included the double Copley Medal winner John Canton and the Dutch-born discoverer of photosynthesis, Jan Ingenhousz, and he naturally spent time with Priestley. 

Franklin saw even more of Priestley from 1773, when the latter wintered in London. The two men enjoyed a very special relationship of shared enquiry, and it was with that time in mind that Priestley later wrote: “it is probable that no person now living was better acquainted with Dr Franklin”. 

Franklin had Priestley for a companion just a day before he was forced to sail to America to escape arrest by the repressive ministers in Lord North’s British government. 

Priestley well knew that Franklin was not the ‘agent provocateur’ of that government’s imagination, but had tried to settle the dispute between Britain and its colonies. Far from seeking separation, Franklin had long advocated a British empire across North America. As Priestley wrote of Franklin: “So great an admirer was he at that time of the British Constitution, that he said he saw no inconvenience from its being extended over a great part of the globe.” 

It was not the Americans’ rejection of the British constitution, but their very belief that the British were forcibly seeking an unconstitutional extension of London’s executive power that led to the colonies’ eventual rebellion. 

Priestley and Franklin continued to correspond, if circumspectly, during the conflict and once again more openly at its conclusion. Franklin, one of the Founding Fathers of the United States, died in Pennsylvania in 1790. 

The third of the well-known statues of Priestley is in Birmingham, where he and his wife moved in 1780 when he became a Unitarian church minister. The years there would end unhappily as Priestley’s support for the initial, reforming, stages of the French Revolution, combined with his longstanding campaign for the removal of the century-old disenfranchisement of religious dissenters, made him a marked man at a time of political uncertainty and social unrest. 

During three days of rioting in July 1791, a mob, with the acquiescence of the local authorities, destroyed the Unitarians’ Old Meeting House and Priestley’s own home, laboratory, library and papers. Priestley fled, and within three years he had moved to Pennsylvania. 

However, during a period of international crisis, President John Adams introduced the Aliens and Sedition Acts and Priestley feared deportation. It was not until after the inauguration of his friend Thomas Jefferson in 1801 that Priestley was able to write to the new President “that it is now only that I can say I see nothing to fear from the hand of power”. It was in America that Priestley ultimately found tolerance and toleration, and it was there, in 1804, that he died. 

The 18th century was a period when scientific enquiry and experimentation was able to flourish. Yet, in times of political change and uncertainty, philosophical speculation in the area of politics and religion could be met with fear-fed violent intolerance. 

Considering our own uncertain and often intolerant times, and recalling the shocking event of last June that led to so many floral tributes being placed at the foot of Priestley’s statue in Birstall, we should – on both sides of the Atlantic – take inspiration from this courageous and dignified man. Priestley fought for an open, respectful and well-considered freedom of expression. His is an example to follow in this age of instant communication and immediate comment. 

George Goodwin is a Fellow of the Royal Historical Society and the author of Benjamin Franklin in London: 
The British Life of America’s Founding Father. 

[Editor's note:  For those Americans unfamiliar with the reference in the last paragraph of the article to the "event of last June that led to so many floral tributes being placed at the foot of Priestley's statue in Birstall," Goodwin is referring to the assassination of Jo Cox, a Member of the British Parliament,  who was assassinated while she spoke at the foot of the Priestley statue in Birstall on June 16, 2016 by a right wing extremist who opposed her position against Brexit.

For a link to the original post, please click here.

We have included here a photo from the original unveiling of the Priestley Memorial Nov 19, 1912,

at Birstall, Leeds, Yorkshire.]

Saturday, June 18, 2016

Little Known Facts About Fruit and Vegetable Stickers

Most fruit and vegetables bought in a supermarket nowadays have a label attached to them much like the one in the picture of the Gala Apple above.  We know why the label is there -- to allow the checkout clerk get the PLU code from it so that you will be charged the right amount for the produce you are buying.

Let's make this very clear.  This is mostly for the convenience of the store and not you that the label is there.  They don't have to train their staff in fruit and vegetable recognition, especially with products that look almost identical like organic vs. non-organic cucumbers.  I suppose this ultimately might benefit us by them not charging us for a more expensive product or by reducing the store overhead and ultimately bringing the product to the consumer for a lower price.

The downside to the label is that you should remove it before eating the produce, but sometimes the label is difficult to remove and may blemish the produce while attempting to remove it.  I also happen to find a bowl full of apples less attractive if they each have their PLU labels still attached. You don't want to remove them because you might remove some of the apple skin and promote the immediate decomposition of the fruit and the unsightliness too.

The code on the label can tell us a lot about the produce.  First, the same code is used in all stores for the same product.  This is because it is the producer that puts the label on the product and not the store.  So, you can tell if the fruit or vegetable is the same at two different stores if they have the same label PLU code.  You can tell if the produce is organic or not (prefix 9 + 4 digits for organic).  You can also tell if the produce is genetically modified (prefix 8 + 4 digits).

The FDA requires that both the label and the glue be food grade and they are not supposed to harm you. Some sources claim that the label must be made of "edible paper" and can be eaten, but it is not recommended.   However, I have found sources that claim that the label can be made of plastic, and that should be somewhat disconcerting to us.

My personal experience diverts somewhat from the FDA mandates.  I used to dispose of the fruit and vegetable labels with the rest of my compostable waste.  However, I have found that the labels DO NOT DECOMPOSE.  This has lead me to believe that many labels, may, in fact, be made of some type of plastic.  So the question is whether something that is indigestible is edible, or more importantly whether it should be eaten at all.  Clearly, we should exclude inedible materials like, glass, rocks, metal, and plastics.  I would probably not want to eat clothing either.  Then there are the plant and animal products that we should most likely not eat either, like bones, leather, hair, corn cobs, fruit pits, nut husks, etc.

Are there produce label inspectors at the FDA, or is this purely on the honor system that these labels are being used?  Is there a downside for the manufactures to use real edible paper labels?

Thursday, January 21, 2016

The Curative “Sacred” Waters

Bookplate, Joseph Priestley, "Rushing Water", c. 1780

Another article by guest contributor Chandra Emani*

The faithful in many countries swear by them. Many a land has its share of what are known as “sacred” rivers. A drink of the water in them have mystically cured dreaded diseases.  But the story I have for you today is about one such river I grew up on. The River Ganges or Ganga Nadhi as it is known in India. Travel to India today and people revere the sacred waters known as Gangajal (“jal” in Hindi means “water”). Gangajal, I was told by my elders, gives you peace when you drink it and many a mythological story talk about drinking the waters literally bringing back the dead and cure many a disease. Being the skeptical biologist, I took this as a general eternal love people have for the waters of their land from which spring civilizations and culture. Everything changed when one fine day I was preparing to teach my recombinant DNA technology class at our university. The topic was of bacteriophages, the microbial forms I have been using in my research for the past decade. As always, I was collecting the scientific history to introduce the concepts and the story of the discovery of bacteriophage blew me away. And it involved the sacred waters of Ganga.

In 1896, when British still ruled India, a bacteriologist stationed in Delhi, Ernest Hanbury Hankin, wrote a paper for the Pasteur Institute Journal where he reported that the waters from the rivers Ganga and Yamuna (this river incidentally passes by the Taj Mahal) could cure cholera.  What he wrote in the paper was widely discussed at Oxford and Cambridge. Hankin’s remarkable observation was that even after boiling the waters, or passing them through porcelain filters, the waters from these rivers still retained a mysterious biological source that dissolved bacteria in the lab and stemmed the spread of cholera in the land. People who swore by the curative properties of the rivers unearthed recorded documents that showed that the Ganga water once reportedly cured leprosy, a fact that Hankin now recorded in his paper as completely believable. Hankin was not taken seriously simply because he was on the wrong side of science politics. He was a “vivisector” who “escaped to India”. Vivisection was the use of dissecting live animals for research, a practice scorned by the scientific elite of the times and Hankin was on the wrong side of the debate. So, his remarkable discovery languished in journals. A generation later, in 1915, another British bacteriologist Frederick Twort at the Brown institute in London rediscovered the mysterious bacterial killer. He was working on developing a smallpox vaccine from a bacteria found in the skin of calves and when he plated those bacteria in the lab, he observed that among the bacterial growth lawns in the plate, certain transparent glassy areas were seen clearly showing something killing and dissolving the bacteria. Across the ocean, French-Canadian microbiologist Felix D’Herelle independently discovered the same kind of mysterious biological source that “ate” bacteria according to him this time in a culture of dysentery bacteria. D’Herelle confirmed that the mysterious substance was in fact a virus and named it bacteriophage (“phage” in Greek means “eater”). The phenomenon was named “Twort-D’Herelle effect.” Both scientists acknowledged the record of the erstwhile Dr. Hankin and confirmed that what was found in the rivers Ganga and Yamuna was in fact the bacteriophage.  D’Herelle also recorded the remarkable case of a man affected with dysentery being cured by bacteriophages. The science behind the curative sacredness of Gangajal was complete.

In 1920s and 1930s, both the Soviet Republic of Georgia and United States widely used bacteriophages to treat bacterial infections especially in the army. This was called Phage therapy.
It did not catch on as medical trials were documented as inconclusive simply because of improper scientific methodology such as not including proper controls and also the lack of understanding the scientific concepts behind phage action. The subsequent years also saw the rise of antibiotics that were easy to make, store and prescribe and the phage therapy lost out. In the 1960s, phage biology was revived by a scientific trio of Max Delbruck, Alfred Hershey and Salvador Luria (Luria’s first research student was incidentally the legendary Jim Watson who discovered DNA). The scientists were working on phages at the legendary Cold Spring Harbor Laboratory in New York, the ground zero for DNA and molecular biological revolution. When they were working to unravel the molecular elements involved in bacteria, they chanced on bacterial cultures that suddenly showed mutations, the sudden changes seen in genes and DNA as if somebody accidentally broke a test tube while culturing the bacteria. After a long day at the lab, Luria was at a cafeteria when he saw players at a slot machine when a eureka moment chanced on him looking at the sudden wins of the slot machine players. The subsequent years saw the trio work out all the scientific basis of how phages work, the account of which Luria fondly recorded in his autobiography One Slot Machine, A Broken Test Tube. The mystery workings of phages is now complete, the feat that earned Luria, Delbruck and Hershey the Nobel Prize in 1969. In recent times, June 2009 saw clinical trials to use bacteriophage cocktails to treat infected venous leg ulcers in humans. Another clinical trial in the same year in Europe saw phage therapy on chronic ear infections. Several other trials are underway to see the efficacy of phage therapy on infected burns, antibiotic resistance and cystic fibrosis.

As for me, I will forever remember the day when I found out that the curative healing powers of Ganga and Yamuna did have a scientific basis, and the rivers were the first to witness a revolutionary discovery that led to a Nobel Prize and now throw open doors to medical revolutions. I now fully understand why they say “the best way to learn is to teach.”

*Chandra Emani is an Assistant Professor of Biology at Western Kentucky University-Owensboro. Apart from teaching introductory and advanced courses in molecular biology and Genetics and researching on utilizing plants to make useful products such as biofuels and anti-cancerous pharmaceuticals, he enjoys explaining science in simple words to his daughter and son. He can be reached at

Saturday, January 16, 2016

The Lab Mouse Story

The other day I happened to stumble onto a very interesting article that appeared in the Owensboro Messenger-Inquirer written by Chandra Emani, an Assistant Professor of Biology at Western Kentucky University-Owensboro. I thought the article was so interesting that I contacted Dr. Emani and a new friendship has developed.  As it turns out he also likes to write short articles about interesting and obscure tidbits of science.  Apart from teaching introductory and advanced courses in molecular biology and Genetics and researching on utilizing plants to make useful products such as biofuels and anti-cancerous pharmaceuticals, he enjoys explaining science in simple words to his daughter and son.   With his permission I am including here his Lab Mouse Story.  Dr. Emani has agreed to also contribute additional articles for this blog. It is our hope that he will bring our readers food for thought in the months and years ahead.  He may be reached at

The Lab Mouse Story
Chandra Emani

Ever since we were kids, whenever we visit or visualize a lab where medical or biological research is carried out, we always view a ubiquitous cute creature that the scientist experiments with, the white lab mouse. What is it with this animal that scientists always seem to test everything on and then have eureka moments in discovering new phenomena, new drugs that cure all ills? How does something tested in mice be good for humans? Let’s go back in time to see when it all started and then how these little creatures became the model research organisms for genetics, psychology and medicine.

In 1700s, the discoverer of blood circulation system William Harvey recorded the first experiments with mice to study both the processes of blood circulation and reproduction to translate the findings for use in human medicine simply because they were animals that were easy to breed and had an ideal generation time (as in going from parents to offspring) as laboratory animals. The discoverer of the microscope Robert Hooke also working in that same period used them to investigate what happens to life forms under conditions of increased air pressure in enclosed spaces. Joseph Priestley who first made oxygen in the lab tested his lab made life saving gas on lab mice.

Another remarkable scientific event that was cut short in the 1800s involved lab mice. In 1850s, the Austrian Monk Gregor Mendel wanted to study how genes transmitted from to parents to their next generation using lab mice. But in the Church where he had his small lab, his supervisor cut short his experiments to “stop the work with the smelly creatures.” Mendel then had to choose another experimental model, the pea plant and his work, though revolutionary, was published in an obscure journal that had to wait 35 years to be rediscovered (research with plants was not as recognized as animal research) and that set back the revolution known as Genetics. It was only in 1902 that the French biologist Lucien Cuenot replicated Mendel’s laws of genetics using lab mice.

But the real revolution of establishing the lab mouse as an ideal experimental model in 1900 in a farm at Granby, Massachusetts where an elementary schoolteacher named Abbie Lathrop from Illinois started a poultry business. The poultry business failed and Abbie started breeding mice for hobbyists and pet owners. The other animals she raise were ferrets, rabbits and guinea pigs (another popular lab animal of choice). She was assisted by her close friends Edith Chapman and Ada Gray. Abbie started with a pair of waltzing mice she got from her farm and soon successfully multiplied the litter to 11,000. It was at this point that some scientific researchers started looking at her unique and meticulous process of breeding and maintenance of mice in wooden boxes with straw mats fed on oats and crackers and soon the word spread. Abbie started selling mice to scientific labs. At one point, she recorded using one and a half tons of oats and over a dozen barrels of crackers in a month and paying pocket money of a pristine 7 cents an hour to local children to clean the cages of the mice. After her mice made way to the Harvard University, the United States government purchased her mice and guinea pigs to test toxic gases in the trenches of the First World War. The adage of “being used as a guinea pigs” came from.

In 1908, Abbie saw that some of her mice started developing some unusual skin lesions or scars. She wrote a letter to the famous experimental pathologist Leo Loeb at the Washington University and he identified them as cancerous tumors remarkably similar in properties to breast cancer tumors in humans. Loeb encouraged Abbie to develop inbred strains of these mice and between 1913 to 1919, the unlikely pair of a farm woman and a scientist authored 10 journal articles, some of them in Journal of Cancer Research and Journal of Experimental Medicine where they found the biological basis of cancer using a lab mouse model, and the rest as they say is history. During this time, a Harvard geneticist William Castle purchased some of Abbie’s mice and an undergraduate working in his lab by the name Clarence Cook Little (who later became famous for establishing the role of tobacco in causing cancer) was instrumental in developing the mouse strain called “Black 6” which is the frequently used lab mouse till date. Though Little patronizingly referred to Abbie as a “talented pet-shop owner”, it is a known fact now that the famous DBA (Dilute, Brown and non-Agouti) inbred mouse strain that is widely used in medical research came from a silver fawn mouse developed by Abbie. Abbie died as an unsung heroine in 1918 due to pernicious anemia, but her notebooks, observations and meticulous breeding records kept at the famous biomedical research institute, the Jackson Laboratory in California revealed that at least five strains of lab mice that are used today in labs around the world heralding many revolutionary studies came from a single female mouse that she bred in her farm.

As modern medical marvels and possibly a cure for the dreaded disease cancer would one day see the light only after clinical trials translate from countless “mouse model experiments”, let’s salute the unsung heroine behind it all, Abbie Lathrop, a home schooled elementary school teacher who worked from a modest farm in Granby, Massachusetts and heralded the greatest scientific revolutions in medical science.

Sunday, October 11, 2015

Joseph Priestley is on the Move Again

Bronze Sculpture of Joseph Priestley, Leeds, England. Walter Harding, sculptor, 1903

In an article in the Birmingham Mail it has been reported that the bronze statue of Joseph Priestley in Chamberlain Square is on the move.  The statue has been removed from its plinth and transported into storage at the Birmingham Museums Trust Collection Centre ahead of the demolition of the Central Library and the start of reconstruction of the area around the Square.  The statue of James Watt was also removed and the statue of Thomas Atwood will also be removed in a similar manner.
They will all be returned to the Square when the construction work is completed.

Both Watt and Priestley resided in Birmingham during the early days of of the Industrial Revolution and were members of the Lunar Society.  Priestley, a clergyman, scientist, educator, and social activist is best known for his discovery of Oxygen.  James Watt and Matthew Boulton are credited with the development of the steam engine.

The Joseph Priestley Statue was originally located in Victoria Square, then called Council House Square, but was later move to Chamberlain Square and recast in bronze due to irreparable weather erosion to the original marble.

Watt on the move

Capturing Images of the Elderly in the Early Days of Photography and Motion Pictures

George Washington was born in 1732.  When he died in December of 1799, there were no photographic images of him ever taken because the technology of the photographic process had not been discovered yet.  If you want to "see" what George Washington really looked like, you are limited to viewing interpretive paintings, drawings and engravings of him.  Perhaps that is why different pictures of him look like they are not of the same person.

Recently, I was rummaging around and found some old 16mm home movies that my father took in the 1930s.  It had some great shots of his father-in-law.  I was excited to retrieve this footage of my maternal grandfather and I'm going to have it digitized so that I can preserve it and pass it on to my grandson. After all, this is footage of his great-great-grandfather and it ties in well with the genesis of the search for information on my grandparents and other ancestors which I have been collecting since I posted a piece called Touchstones of Time on this blog.

Unless you just happened to have read that post and remembered a lot of the details, I wouldn't expect you to remember that my maternal grandfather was actually born in 1862.  So, in short, I have a motion picture of a person who was born in 1862.

The question I posed to myself is what is the earliest birthdate of a living person (i.e., living at the time of the shooting of the images) whose image is captured on film?  And, of course, the related question, what is the earliest birthdate of a living person who is captured in a photograph?

I have no doubt that there are motion pictures that exist that are of individuals far older than my grandfather.  As a candidate for the earliest birthdate of an individual captured in a photographic image I immediately thought of an image I have seen of Dolley Madison taken on

Dolley Madison, July 4, 1848, age 80
July 4, 1848, who was 80 years old at the time.  She was born on May 20, 1768, almost 250 years ago.  Dolley Madison, of course, was the wife of the fourth President of the United States, James Madison.
Dolley Madison, 1848 daguerreotype by Mathew Brady
A slightly older John Quincy Adams, born on July 11, 1767, was the sixth President of the United States and was captured in the photograph below.
John Quincy Adams, 1843

And, a still older individual, Samuel Wilson, who was born September 13, 1766, was a resident of Troy, New York, and is recognized as the origin of the term "Uncle Sam". The picture below was taken in 1843.  He was 77 years old when the picture was taken.

Uncle Sam Wilson, 1843
Even older yet is a daguerreotype of John Armstrong, Jr. (November 25, 1758 – April 1, 1843)  who was an American soldier and statesman who was a delegate to the Continental Congress, U.S. Senator from New York, and Secretary of War under James Madison.
John Armstrong, Jr. with dog, 1840
This means that Armstrong was about 82 years old when this picture was taken and this was within the first year of the availability of the daguerreotype process.  Daguerreotypy developed by the French painter Louis-Jacques-Mande Daguerre, was the first publicly announced photographic process ever developed, in 1839. However, the oldest image using this process by Daguerre himself was taken two years earlier, in 1837.

 L’Atelier de l'artiste, first photographic image by Daguerre
The longest unambiguously documented human lifespan is that of Jeanne Calment of France (1875–1997), who lived to the age of 122 years, 164 days. The picture below was taken in 1996 on the occasion of her 121st birthday:
Jeanne Calment, at 121st birthday in 1996
Jean Calment met Vincent Van Gogh when she was 11 or 12 years old.

The oldest extant American Daguerreotype portrait was a self-portrait taken by Robert Cornelius in October or November 1839. The announcement of the process occurred in August, 1939, a few months prior.  See below:

Robert Cornelius, Self-Portrait, 1839
Unfortunately, Cornelius was born in 1809, so he does not even come close to claiming fame for the oldest person depicted in a photograph.
On a purely speculative basis I am presuming that the oldest person in a photographic image was shot shortly after the technology was developed in 1839 and that person would have been in their late 80s.
That would put their birthdate somewhere around the beginning of the 1750s.  To put this in perspective, it would have to have been a person born about a decade after George Washington.

The French physiologist Etienne-Jules Marey took the first series of photographs with a single instrument in 1882 with a camera shaped like a rifle that recorded 12 successive photographs per second.   However, the world's oldest photographic moving picture sequence is by the French photographer Felix Nadar who created his revolving portrait in 1865.  Thomas Edison is credited with having taken the first true motion picture in 1889, but the image's quality is so poor that the identity of the individual who was the subject in the movie is not discernable.

Again, on a purely speculative basis I am presuming that the oldest person in a motion picture sequence was shot in the early 1890s and that the person could have been in their late 80s.  That would put their birthdate somewhere just after the beginning of the 19th century; probably someone around Abraham Lincoln's date of birth. 

Here is a Youtube sequence of old motion picture cuts from New York City, the oldest being from 1896. If any readers would like to nominate a picture or motion picture that would be a candidate for the oldest person in each category we would like to hear from you.

last modified 1/9/2016

Tuesday, September 15, 2015

Is a Hyperloop Pneumatic Tube for the Transport of People and Goods Really Possible?

In 1897 the United States Post Office started to install pneumatic tubes in a 
number of metropolitan areas in order to expedite the delivery of the mail. 
By 1898 the tubes were in operation.   

Robin Pogrebin, in an article in the New York Times on May 7, 2001, wrote a
fascinating piece on the history of the pneumatic tube mail system.  In the article 
he highlighted some of the features of the system.  The system was thoroughly 
modern, some might even say high-tech.  It was like subterranean internet for 
priority and first-class mail powered by air pressure. Pneumatic tubes similar to 
these are still used in some banks, and other specialty areas.  I even saw some at
Home Depot not too long ago.

The mail tubes were installed in the cities of Boston, Philadelphia, Chicago, St. 
Louis, and New York.  In Manhattan, they extended about 27 miles, from the old 
Custom House in Battery Park to Harlem and back through Times Square, Grand 
Central Terminal and the main post office near Pennsylvania Station. In the 
picture above at the at the City Hall station, the mail also went in a pneumatic tube 
over the Brooklyn Bridge to the general post office in Brooklyn. 

The system used pressurized air to move a mail canister through an underground 
eight-inch cast-iron pipe.  In New York City, two pipes were used along each 
route, one for sending, the other for receiving.  The pipes were buried 4 to 12 feet 
underground, though in some places the tubes were placed within subway tunnels.  
Improvements in the speed of the motor-wagon and its successor, the automobile, 
signaled the end of the pneumatic tube.  However, the tube system remained in 
operation in New York City until December 1, 1953.

Artist's impression of a Hyperloop capsule: Air Compressor on the front, passenger compartment in the middle,
battery compartment at the back and 
air bearing skis at the bottom.

The modern day equivalent to the pneumatic air tube of the postal service 
of the late 19th century might arguably be the hyperloop (see the
illustration above), a conceptual high-speed transportation system proposed 
by Elon Musk in 2013 as a means of efficiently transporting people and 
goods quickly over large distances.  The Hyperloop would incorporate 
reduced pressure tubes in which pressurized capsules would ride on an air 
cushion driven by linear induction motors and air compressors.

While the hyperloop has been roundly criticized as a "pipe dream."  

Some elements in the Musk conception of the technology to realize the 
hyperloop would utilize newer technological components such as a linear 
induction motor, history shows us that the general concept is far from new, 
and far from impractical.