Biocompatibility (biomedical therapy): Ability of a material to perform with an appropriate host response in a specific application.
Biocompatibility: Ability to be in contact with a living system without producing an adverse effect.
Biocompatibility is related to the behavior of biomaterials
in various contexts. The term refers to the ability of a material to
perform with an appropriate host response in a specific situation. The ambiguity of the term reflects the ongoing development of insights into how biomaterials interact with the human body and eventually how those interactions determine the clinical success of a medical device (such as pacemaker, hip replacement or stent). Modern medical devices and prostheses
are often made of more than one material so it might not always be
sufficient to talk about the biocompatibility of a specific material.
Even the same materials, such as diamond-like carbon coatings, may show
different levels of biocompatibility based on the manufacturing
conditions and characteristics.
Since the immune response
and repair functions in the body are so complicated it is not adequate
to describe the biocompatibility of a single material in relation to a
single cell type or tissue. Sometimes one hears of biocompatibility
testing that is a large battery of in vitro test that is used in accordance with ISO 10993
(or other similar standards) to determine if a certain material (or
rather biomedical product) is biocompatible. These tests do not
determine the biocompatibility of a material, but they constitute an important step towards the animal testing and finally clinical trials that will determine the biocompatibility of the material in a given application, and thus medical devices such as implants or drug delivery devices. Research results have concluded that during performing in vitro cytotoxicity
testing of biomaterials, "the authors should carefully specify the
conditions of the test and comparison of different studies should be
carried out with caution".
History
The word biocompatibility
seems to have been mentioned for the first time in peer-review journals
and meetings in 1970 by RJ Hegyeli (Amer Chem Soc Annual Meeting
abstract) and CA Homsy. It took almost two decades before it began to be commonly used in scientific literature (see the graph below).
Recently Williams (again) has been trying to reevaluate the
current knowledge status regarding what factors determine clinical
success. Doing so notes that an implant may not always have to be
positively bioactive but it must not do any harm (either locally or
systemically).
Five definitions of biocompatibility
"The quality of not having toxic or injurious effects on biological systems".
"The ability of a material to perform with an appropriate host response in a specific application", Williams' definition.
"Comparison of the tissue response produced through the close
association of the implanted candidate material to its implant site
within the host animal to that tissue response recognised and
established as suitable with control materials" - ASTM
"Refers to the ability of a biomaterial to perform its desired
function with respect to a medical therapy, without eliciting any
undesirable local or systemic effects in the recipient or beneficiary of
that therapy, but generating the most appropriate beneficial cellular
or tissue response in that specific situation, and optimising the
clinically relevant performance of that therapy".
"Biocompatibility is the capability of a prosthesis implanted in the
body to exist in harmony with tissue without causing deleterious
changes".
Comments on the above five definitions
The
Dorland Medical definition not recommended according to Williams
Dictionary since it only defines biocompatibility as the absence of host
response and does not include any desired or positive interactions
between the host tissue and the biomaterials.
This is also called the “Williams definition” or “William’s definition”. It was defined in the European Society for Biomaterials Consensus Conference I and can more easily be found in ‘The Williams Dictionary of Biomaterials’.
The ASTM is not recommended according to Williams Dictionary since it only refers to local tissue responses, in animal models.
The fourth is an expansion or rather more precise version of the
first definition noting both that low toxicity and the one should be
aware of the different demands between various medical applications of
the same material.
All these definitions deal with materials and not with devices. This
is a drawback since many medical devices are made of more than one
material. Much of the pre-clinical testing of the materials is not
conducted on the devices but rather the material itself. But at some
stage the testing will have to include the device since the shape,
geometry and surface treatment etc. of the device will also affect its
biocompatibility.
‘Biocompatible’
In
the literature, one quite often stumbles upon the adjective form,
‘biocompatible’. However, according to Williams’ definition, this does
not make any sense because biocompatibility is contextual, i.e. much
more than just the material itself will determine the clinical outcome
of the medical device of which the biomaterial is a part. This also
points to one of the weaknesses with the current definition because a
medical device usually is made of more than one material.
Metallic glasses based on magnesium with zinc and calcium
addition are tested as the potential biocompatible metallic biomaterials
for biodegradable medical implants
Biocompatibility (or tissue compatibility) describes the ability
of a material to perform with an appropriate host response when applied
as intended. A biocompatible material may not be completely "inert"; in
fact, the appropriateness of the host response is decisive.
Suggested sub-definitions
The
scope of the first definition is so wide that D Williams tried to find
suitable subgroups of applications in order to be able to make more
narrow definitions. In the MDT article from 2003 the chosen supgroups
and their definitions were:
The biocompatibility of a long-term implantable medical device
refers to the ability of the device to perform its intended function,
with the desired degree of incorporation in the host, without eliciting
any undesirable local or systemic effects in that host.
Biocompatibility of short-term implantable devices
The biocompatibility of a medical device that is intentionally
placed within the cardiovascular system for transient diagnostic or
therapeutic purposes refers to the ability of the device to carry out
its intended function within flowing blood, with minimal interaction
between device and blood that adversely affects device performance, and
without inducing uncontrolled activation of cellular or plasma protein
cascades.
The biocompatibility of a scaffold or matrix for a
tissue-engineering products refers to the ability to perform as a
substrate that will support the appropriate cellular activity, including
the facilitation of molecular and mechanical signalling systems, in
order to optimise tissue regeneration, without eliciting any undesirable
effects in those cells, or inducing any undesirable local or systemic
responses in the eventual host.
In these definitions the notion of biocompatibility is related to
devices rather than to materials as compared to top three definitions.
There was a consensus conference on biomaterial definitions in Sorrento
September 15–16, 2005.
Sectional view of the igniter of a Model 1935 grenade
Military technology is the application of technology for use in warfare.
It comprises the kinds of technology that are distinctly military in
nature and not civilian in application, usually because they lack useful
or legal civilian applications, or are dangerous to use without
appropriate military training.
The line is porous; military inventions
have been brought into civilian use throughout history, with sometimes
minor modification if any, and civilian innovations have similarly been
put to military use.
Military technology is usually
researched and developed by scientists and engineers specifically for use in battle by the armed forces. Many new technologies came as a result of the military funding of science.
This section is divided into the broad cultural developments that affected military technology.
Ancient technology
The first use of stone tools may have begun during the Paleolithic
Period. The earliest stone tools are from the site of Lomekwi, Turkana,
dating from 3.3 million years ago. Stone tools diversified through the Pleistocene Period, which ended ~12,000 years ago.
The earliest evidence of warfare between two groups is recorded at the site of Nataruk
in Turkana, Kenya, where human skeletons with major traumatic injuries
to the head, neck, ribs, knees and hands, including an embedded obsidian
bladelet on a skull, are evidence of inter-group conflict between
groups of nomadic hunter-gatherers 10,000 years ago.
Humans entered the Bronze Age
as they learned to smelt copper into an alloy with tin to make weapons.
In Asia where copper-tin ores are rare, this development was delayed
until trading in bronze began in the third millennium BCE. In the Middle East and Southern European regions, the Bronze Age follows the Neolithic period, but in other parts of the world, the Copper Age is a transition from Neolithic to the Bronze Age. Although the Iron Age generally follows the Bronze Age, in some areas the Iron Age
intrudes directly on the Neolithic from outside the region, with the
exception of Sub-Saharan Africa where it was developed independently.
The first large-scale use of iron weapons began in Asia Minor
around the 14th century BCE and in Central Europe around the 11th
century BCE followed by the Middle East (about 1000 BCE) and India and
China.
The Assyrians
are credited with the introduction of horse cavalry in warfare and the
extensive use of iron weapons by 1100 BCE. Assyrians were also the first
to use iron-tipped arrows.
The Wujing Zongyao (Essentials of the Military Arts), written by Zeng Gongliang, Ding Du, and others at the order of Emperor Renzong around 1043 during the Song dynasty
illustrate the eras focus on advancing intellectual issues and military
technology due to the significance of warfare between the Song and the
Liao, Jin, and Yuan to their north. The book covers topics of military
strategy, training, and the production and employment of advanced
weaponry.
Advances in military technology aided the Song dynasty in its defense against hostile neighbors to the north. The flamethrower found its origins in Byzantine-era Greece, employing Greek fire (a chemically complex, highly flammable petrol fluid) in a device with a siphon hose by the 7th century. The earliest reference to Greek Fire in China was made in 917, written by Wu Renchen in his Spring and Autumn Annals of the Ten Kingdoms.
In 919, the siphon projector-pump was used to spread the 'fierce fire
oil' that could not be doused with water, as recorded by Lin Yu in his Wuyue Beishi, hence the first credible Chinese reference to the flamethrower employing the chemical solution of Greek fire (see also Pen Huo Qi).
Lin Yu mentioned also that the 'fierce fire oil' derived ultimately
from one of China's maritime contacts in the 'southern seas', ArabiaDashiguo. In the Battle of Langshan Jiang in 919, the naval fleet of the Wenmu King from Wuyue defeated a Huainan army from the Wu state; Wenmu's success was facilitated by the use of 'fire oil' ('huoyou') to burn their fleet, signifying the first Chinese use of gunpowder in a battle. The Chinese applied the use of double-pistonbellows
to pump petrol out of a single cylinder (with an upstroke and
downstroke), lit at the end by a slow-burning gunpowder match to fire a
continuous stream of flame. This device was featured in description and illustration of the Wujing Zongyao military manuscript of 1044. In the suppression of the Southern Tang
state by 976, early Song naval forces confronted them on the Yangtze
River in 975. Southern Tang forces attempted to use flamethrowers
against the Song navy, but were accidentally consumed by their own fire
when violent winds swept in their direction.
Although the destructive effects of gunpowder were described in the earlier Tang dynasty by a Daoistalchemist, the earliest developments of the gun barrel and the projectile-fire cannon were found in late Song China. The first art depiction of the Chinese 'fire lance' (a combination of a temporary-fire flamethrower and gun) was from a Buddhist mural painting of Dunhuang, dated circa 950.
These 'fire-lances' were widespread in use by the early 12th century,
featuring hollowed bamboo poles as tubes to fire sand particles (to
blind and choke), lead pellets, bits of sharp metal and pottery shards,
and finally large gunpowder-propelled arrows and rocket weaponry.
Eventually, perishable bamboo was replaced with hollow tubes of cast
iron, and so too did the terminology of this new weapon change, from 'fire-spear' huo qiang to 'fire-tube' huo tong. This ancestor to the gun was complemented by the ancestor to the
cannon, what the Chinese referred to since the 13th century as the
'multiple bullets magazine erupter' bai zu lian zhu pao, a tube of bronze or cast iron that was filled with about 100 lead balls.
The earliest known depiction of a gun is a sculpture from a cave in Sichuan, dating to 1128, that portrays a figure carrying a vase-shaped bombard, firing flames and a cannonball. However, the oldest existent archaeological discovery of a metal barrel handgun is from the Chinese Heilongjiang excavation, dated to 1288. The Chinese also discovered the explosive potential of packing hollowed cannonball shells with gunpowder. Written later by Jiao Yu in his Huolongjing
(mid-14th century), this manuscript recorded an earlier Song-era
cast-iron cannon known as the 'flying-cloud thunderclap eruptor' (fei
yun pi-li pao). The manuscript stated that:
As noted before, the change in terminology for these new weapons
during the Song period were gradual. The early Song cannons were at
first termed the same way as the Chinese trebuchetcatapult. A later Ming dynasty scholar known as Mao Yuanyi would explain this use of terminology and true origins of the cannon in his text of the Wubei Zhi, written in 1628:
The 14th-century Huolongjing was also one of the first Chinese texts to carefully describe to the use of explosive land mines, which had been used by the late Song Chinese against the Mongols in 1277, and employed by the Yuan dynasty
afterwards. The innovation of the detonated land mine was accredited to
one Luo Qianxia in the campaign of defense against the Mongol invasion
by Kublai Khan, Later Chinese texts revealed that the Chinese land mine employed either a rip cord or a motion booby trap of a pin releasing falling weights that rotated a steel flint wheel, which in turn created sparks that ignited the train of fuses for the land mines. Furthermore, the Song employed the earliest known gunpowder-propelled rockets in warfare during the late 13th century, its earliest form being the archaic Fire Arrow.
When the Northern Song capital of Kaifeng fell to the Jurchens in 1126,
it was written by Xia Shaozeng that 20,000 fire arrows were handed over
to the Jurchens in their conquest. An even earlier Chinese text of the
Wujing Zongyao
("Collection of the Most Important Military Techniques"), written in
1044 by the Song scholars Zeng Kongliang and Yang Weide, described the
use of three spring or triple bow arcuballista that fired arrow bolts holding gunpowder packets near the head of the arrow. Going back yet even farther, the Wu Li Xiao Shi (1630, second edition 1664) of Fang Yizhi stated that fire arrows were presented to Emperor Taizu of Song (r. 960–976) in 960.
Rapid development in military technology had a dramatic impact on armies and navies in the industrialized world in 1740–1914.
For land warfare, cavalry faded in importance, while infantry became
transformed by the use of highly accurate more rapidly loading rifles,
and the use of smokeless powder. Machine guns were developed in the
1860s in Europe. Rocket artillery and the Mysorean rockets, both pioneered by Indian Muslim Tipu Sultan, became more powerful as new high explosives (based on nitroglycerin) arrived during the Anglo-Mysore Wars,
and the French introduced much more accurate rapid-fire field
artillery. Logistics and communications support for land warfare
dramatically improved with use of railways and telegraphs.
Industrialization provided a base of factories that could be converted
to produce munitions, as well as uniforms, tents, wagons and essential
supplies. Medical facilities were enlarged and reorganized based on
improved hospitals and the creation of modern nursing, typified by Florence Nightingale in Britain during the Crimean War of 1854–56.
Naval
Naval warfare was transformed by many innovations,
most notably the coal-based steam engine, highly accurate long-range
naval guns, heavy steel armour for battleships, mines, and the
introduction of the torpedo, followed by the torpedo boat and the
destroyer. Coal after 1900 was eventually displaced by more efficient
oil, but meanwhile navies an international scope had to depend on a
network of coaling stations to refuel. The British Empire provided them
in abundance, as did the French Empire to a lesser extent. War colleges
developed, as military theory became a specialty; cadets and senior
commanders were taught the theories of Jomini, Clausewitz and Mahan, and
engaged in tabletop war games. Around 1900, entirely new innovations
such as submarines and airplanes appeared, and were quickly adapted to
warfare by 1914. The British HMS Dreadnought (1906)
incorporated so much of the latest technology in weapons, propulsion
and armour that it at a stroke made all other battleships obsolescent.
Organization and finance
New
financial tools were developed to fund the rapidly increasing costs of
warfare, such as popular bond sales and income taxes, and the funding of
permanent research centers. Many 19th century innovations were largely invented and promoted by lone individuals with small teams of assistants, such as David Bushnell and the submarine, John Ericsson and the battleship, Hiram Maxim and the machine gun, and Alfred Nobel
and high explosives. By 1900 the military began to realize that they
needed to rely much more heavily on large-scale research centers, which
needed government funding. They brought in leaders of organized innovation such as Thomas Edison in the U.S. and chemist Fritz Haber of the Kaiser Wilhelm Institute in Germany.
Postmodern technology
The
postmodern stage of military technology emerged in the 1940s, and one
with recognition thanks to the high priority given during the war to
scientific and engineering research and development regarding nuclear
weapons, radar, jet engines, proximity fuses, advanced submarines,
aircraft carriers, and other weapons. The high-priority continues into
the 21st century.
It involves the military application of advanced scientific research
regarding nuclear weapons, jet engines, ballistic and guided missiles,
radar, biological warfare, and the use of electronics, computers and
software.
During the Cold War, the world's two great superpowers – the Soviet Union
and the United States of America – spent large proportions of their GDP
on developing military technologies. The drive to place objects in
orbit stimulated space research and started the Space Race. In 1957, the USSR launched the first artificial satellite, Sputnik 1.
By the end of the 1960s, both countries regularly deployed satellites. Spy satellites
were used by militaries to take accurate pictures of their rivals'
military installations. As time passed the resolution and accuracy of
orbital reconnaissance alarmed both sides of the iron curtain. Both the United States and the Soviet Union began to develop anti-satellite weapons to blind or destroy each other's satellites. Laser weapons, kamikaze
style satellites, as well as orbital nuclear explosion were researched
with varying levels of success. Spy satellites were, and continue to
be, used to monitor the dismantling of military assets in accordance
with arms control treaties signed between the two superpowers. To use
spy satellites in such a manner is often referred to in treaties as
"national technical means of verification".
The superpowers developed ballistic missiles to enable them to use nuclear weaponry across great distances. As rocket science developed, the range of missiles increased and intercontinental ballistic missiles
(ICBM) were created, which could strike virtually any target on Earth
in a timeframe measured in minutes rather than hours or days. To cover
large distances ballistic missiles are usually launched into sub-orbital spaceflight.
A significant portion of military technology is about transportation,
allowing troops and weaponry to be moved from their origins to the
front. Land transport has historically been mainly by foot, land
vehicles have usually been used as well, from chariots to tanks.
When conducting a battle over a body of water, ships are used.
There are historically two main categories of ships: those for
transporting troops, and those for attacking other ships.
Soon after the invention of aeroplanes, military aviation became a
significant component of warfare, though usually as a supplementary
role. The two main types of military aircraft are bombers, which attack
land- or sea-based targets, and fighters, which attack other aircraft.
Military vehicles
are land combat or transportation vehicles, excluding rail-based, which
are designed for or in significant use by military forces.
Military aircraft
includes any use of aircraft by a country's military, including such
areas as transport, training, disaster relief, border patrol, search and
rescue, surveillance, surveying, peacekeeping, and (very rarely) aerial
warfare.
Fortifications are military constructions and buildings
designed for defence in warfare. They range in size and age from the
Great Wall of China to a Sangar.
Sensors and communication systems are used to detect enemies,
coordinate movements of armed forces and guide weaponry. Early systems
included flag signaling, telegraph and heliographs.
A high-resolution computer drawing of the Atlas robot designed by Boston Dynamics and DARPA, as seen from behind.
The Defense Advanced Research Projects Agency
is an agency of the United States Department of Defense responsible for
the development of new technologies for use by the military. DARPA
leads the development of military technology in the United States and
today, has dozens of ongoing projects; everything from humanoid robots,
to bullets that are able to change path before reaching their target.
China has a similar agency.
Emerging territory
Current militaries continue to invest in new technologies for the future. Such technologies include cognitive radar , 5g cellular networks, microchips, semiconductors, and large scale analytic engines.
Additionally, many militaries seek to improve current laser
technology. For example, Israeli Defense Forces utilize laser technology
to disable small enemy machinery, but seek to move to more large scale
capabilities in the coming years.
Militaries across the world continue to perform research on
autonomous technologies which allow for increased troop mobility or
replacement of live soldiers. Autonomous vehicles and robots are expected to play a role in future conflicts; this has the potential to decrease loss of life in future warfare. Observers of transhumanism note high rates of technological terms in military literature, but low rates for explicitly transhuman-related terms.
Today's hybrid style of warfare also calls for investments in
information technologies. Increased reliance on computer systems has
incentivized nations to push for increased efforts at managing large
scale networks and having access to large scale data.
New strategies of cyber and hybrid warfare includes, network
attacks, media analysis, and media/ grass-roots campaigns on medias such
as blog posts
Cyberspace
In
2011, the US Defense Department declared cyberspace a new domain of
warfare; since then DARPA has begun a research project known as "Project
X" with the goal of creating new technologies that will enable the
government to better understand and map the cyber territory. Ultimately
giving the Department of Defense the ability to plan and manage
large-scale cyber missions across dynamic network environments.
The Continental Army was the army of the United Colonies representing the Thirteen Colonies and later the United States during the American Revolutionary War. It was formed on June 14, 1775 by a resolution passed by the Second Continental Congress, meeting in Philadelphia
after the war's outbreak. The Continental Army was created to
coordinate military efforts of the colonies in the war against the British, who sought to maintain control over the American colonies. General George Washington was appointed commander-in-chief of the Continental Army and maintained this position throughout the war.
The Continental Army was supplemented by local militias
and volunteer troops that were either loyal to individual states or
otherwise independent. Most of the Continental Army was disbanded in
1783 after the Treaty of Paris formally ended the war. The Continental Army's 1st and 2nd Regiments went on to form what was to become the Legion of the United States in 1792, which ultimately served as the foundation for the creation of the U.S. Army.
The Continental Army consisted of soldiers from all 13 colonies and,
after 1776, from all 13 states. The American Revolutionary War began at
the Battles of Lexington and Concord
on April 19, 1775, at a time when the colonial revolutionaries had no
standing army. Previously, each colony had relied upon the militia (which was made up of part-time citizen-soldiers) for local defense; or the raising of temporary provincial troops during such crises as the French and Indian War of 1754–1763. As tensions with Great Britain
increased in the years leading to the war, colonists began to reform
their militias in preparation for the perceived potential conflict.
Training of militiamen increased after the passage of the Intolerable Acts in 1774. Colonists such as Richard Henry Lee proposed forming a national militia force, but the First Continental Congress rejected the idea.
On April 23, 1775, the Massachusetts Provincial Congress authorized the raising of a colonial army
consisting of 26 company regiments. New Hampshire, Rhode Island, and
Connecticut soon raised similar but smaller forces. On June 14, 1775,
the Second Continental Congress
decided to proceed with the establishment of a Continental Army for
purposes of common defense, adopting the forces already in place outside
Boston (22,000 troops) and New York (5,000). It also raised the first
ten companies of Continental troops on a one-year enlistment, riflemen
from Pennsylvania, Maryland, Delaware, and Virginia to be used as light infantry, who became the 1st Continental Regiment
in 1776. On June 15, 1775, Congress elected by unanimous vote George
Washington as Commander-in-Chief, who accepted and served throughout the
war without any compensation except for reimbursement of expenses. Supporting Washington as commander in chief were four major generals (Artemas Ward, Charles Lee, Philip Schuyler, and Israel Putnam) and eight brigadier generals (Seth Pomeroy, Richard Montgomery, David Wooster, William Heath, Joseph Spencer, John Thomas, John Sullivan, and Nathanael Greene)
As the Continental Congress increasingly adopted the responsibilities
and posture of a legislature for a sovereign state, the role of the
Continental Army became the subject of considerable debate. Some
Americans had a general aversion to maintaining a standing army; but on
the other hand, the requirements of the war against the British required
the discipline and organization of a modern military. As a result, the
army went through several distinct phases, characterized by official
dissolution and reorganization of units.
Broadly speaking, Continental forces consisted of several successive armies or establishments:
The Continental Army of 1775, comprising the initial New England
Army, was organized by Washington into three divisions, six brigades,
and 38 regiments. Major General Philip Schuyler's ten regiments in New
York were sent to invade Canada.
The Continental Army of 1776, was reorganized after the initial
enlistment period of the soldiers in the 1775 army had expired.
Washington had submitted recommendations to the Continental Congress
almost immediately after he had accepted the position of
Commander-in-Chief, but the Congress took time to consider and implement
these. Despite attempts to broaden the recruiting base beyond New
England, the 1776 army remained skewed toward the Northeast both in
terms of its composition and of its geographical focus. This army
consisted of 36 regiments, most standardized to a single battalion of
768 men strong and formed into eight companies, with a rank-and-file strength of 640.
The Continental Army of 1777–1780 evolved out of several critical
reforms and political decisions that came about when it became apparent
that the British were sending substantial forces to put an end to the American Revolution.
The Continental Congress passed the "Eighty-eight Battalion Resolve",
ordering each state to contribute one-battalion regiments in proportion
to their population, and Washington subsequently received authority to
raise an additional 16 battalions. Enlistment terms extended to three
years or to "the length of the war" to avoid the year-end crises that
depleted forces (including the notable near-collapse of the army at the
end of 1776, which could have ended the war in a Continental, or
American, loss by forfeit)
The Continental Army of 1781–1782 saw the greatest crisis on the
American side in the war. Congress was bankrupt, making it very
difficult to replenish the soldiers whose three-year terms had expired.
Popular support for the war reached an all-time low, and Washington had
to put down mutinies both in the Pennsylvania Line and in the New Jersey Line. Congress voted to cut funding for the Army, but Washington managed nevertheless to secure important strategic victories.
The Continental Army of 1783–1784 was succeeded by the United States
Army, which persists to this day. As peace was restored with the
British, most of the regiments were disbanded in an orderly fashion,
though several had already been diminished.
The Continental Army was a dirty, unorganized rabble that lacked the
discipline typically expected of an army. When they first assembled, the
count of how many soldiers George Washington
had was delayed a little over a week. Instead of obeying their
commanders and officers without question, each unit was a community that
had democratically
chosen its leaders. The regiments, coming from different states, were
uneven in numbers. Logically, they should be evened, which would mean
moving soldiers around. In the spirit of American republicanism,
if George Washington separated the soldiers from the officers they had
chosen they did not believe they should have to serve. George Washington
had to give in to the soldiers and negotiate with them. He needed them
to have an army.
Soldiers in the Continental Army were volunteers; they agreed to
serve in the army and standard enlistment periods lasted from one to
three years. Early in the war, the enlistment periods were short, as the
Continental Congress
feared the possibility of the Continental Army evolving into a
permanent army. The army never numbered more than 48,000 men overall and
13,000 troops in one area. The turnover proved a constant problem,
particularly in the winter of 1776–77, and longer enlistments were
approved. As the new country (not yet fully independent) had no money,
the government agreed to give grants to the soldiers which they could
exchange for money. In 1781 and 1782, Patriot officials and officers in the Southern Colonies
repeatedly implemented policies that offered slaves as rewards for
recruiters who managed to enlist a certain number of volunteers in the
Continental Army; in January 1781, Virginia's General Assembly passed a measure which announced that voluntary enlistees in the Virginia Line's regiments would be given a "healthy sound negro" as a reward.
The officers of both the Continental Army and the state militias
were typically yeoman farmers with a sense of honor and status and an
ideological commitment to oppose the policies of the British Crown.
The enlisted men were very different. They came from the working class
or minority groups (English, Ulster Protestant, African American). They
were motivated to volunteer by specific contracts that promised bounty
money; regular pay at good wages; food, clothing, and medical care;
companionship; and the promise of land ownership after the war. They
were unruly and would mutiny if the contractual terms were not met. By
1780–1781, threats of mutiny and actual mutinies were becoming serious. Upwards of a fourth of Washington's army were of Scots-Irish (English and Scottish descent) Ulster origin, many being recent arrivals and in need of work.
The Continental Army was racially integrated, a condition the United States Army would not see again until the late 1940s. During the Revolution, African American slaves were promised freedom in exchange for military service by both the Continental and British armies.
Approximately 6,600 people of color (including African American,
indigenous, and multiracial men) served with the colonial forces, and
made up one-fifth of the Northern Continental Army.
In addition to the Continental Army regulars, state militia units
were assigned for short-term service and fought in campaigns throughout
the war. Sometimes the militia units operated independently of the
Continental Army, but often local militias were called out to support
and augment the Continental Army regulars during campaigns. The militia
troops developed a reputation for being prone to premature retreats, a
fact that General Daniel Morgan integrated into his strategy at the Battle of Cowpens and used to fool the British in 1781.
The financial responsibility for providing pay, food, shelter,
clothing, arms, and other equipment to specific units was assigned to
states as part of the establishment of these units. States differed in
how well they lived up to these obligations. There were constant funding
issues and morale problems as the war continued. This led to the army
offering low pay, often rotten food, hard work, cold, heat, poor
clothing and shelter, harsh discipline, and a high chance of becoming a
casualty.
Keeping the continentals clothed was a difficult task and to do
this Washington appointed James Mease, a merchant from Philadelphia.
Mease worked closely with state-appointed agents to purchase clothing
and things such as cow hides to make clothing and shoes for soldiers.
Mease eventually resigned in 1777 and had compromised much of the
organization of the Clothing Department. After this, on many accounts,
the soldiers of the Continental Army were often poorly clothed, had few
blankets, and often did not even have shoes. The problems with clothing
and shoes for soldiers were often not the result of not having enough
but of organization and lack of transportation. To reorganize the Board
of War was appointed to sort out the clothing supply chain. During this
time they sought out the help of France and for the remainder of the
war, clothing was coming from over-sea procurement.
At the time of the siege of Boston, the Continental Army at Cambridge, Massachusetts,
in June 1775, is estimated to have numbered from 14,000 to 16,000 men
from New England (though the actual number may have been as low as
11,000 because of desertions). Until Washington's arrival, it remained
under the command of Artemas Ward.
The British force in Boston was increasing by fresh arrivals. It
numbered then about 10,000 men. The British controlled Boston and
defended it with their fleet, but they were outnumbered and did not
attempt to challenge the American control of New England. Washington
selected young Henry Knox,
a self-educated strategist, to take charge of the artillery from an
abandoned British fort in upstate New York, and dragged across the snow
to and placed them in the hills surrounding Boston in March 1776.
The British situation was untenable. They negotiated an uneventful
abandonment of the city and relocated their forces to Halifax in Canada.
Washington relocated his army to New York. For the next five years, the
main bodies of the Continental and British armies campaigned against
one another in New York, New Jersey, and Pennsylvania. These campaigns
included the notable battles of Trenton, Princeton, Brandywine, Germantown, and Morristown, among many others.
The army increased its effectiveness and success rate through a
series of trials and errors, often at a great human cost. General
Washington and other distinguished officers were instrumental leaders in
preserving unity, learning and adapting, and ensuring discipline
throughout the eight years of war. In the winter of 1777–1778, with the
addition of Baron von Steuben, a Prussian expert, the training and discipline of the Continental Army was dramatically upgraded to modern European standards. This was during the infamous winter at Valley Forge. Washington always viewed the Army as a temporary measure and strove to maintain civilian control of the military, as did the Continental Congress, though there were minor disagreements about how this was to be carried out.
Throughout its existence, the Army was troubled by poor
logistics, inadequate training, short-term enlistments, interstate
rivalries, and Congress's inability to compel the states to provide
food, money, or supplies. In the beginning, soldiers enlisted for a
year, largely motivated by patriotism; but as the war dragged on,
bounties and other incentives became more commonplace. Major and minor
mutinies—56 in all—diminished the reliability of two of the main units
late in the war.
The French played a decisive role in 1781 as Washington's Army was augmented by a French expeditionary force under Lieutennat General Rochambeau and a squadron of the French navy under the Comte de Barras. By disguising his movements, Washington moved the combined forces south to Virginia
without the British commanders in New York realizing it. This resulted
in the capture of the main British invasion force in the south at the siege of Yorktown, which resulted in the American and their allied victory in the land war in North America and assured independence.
A small residual force remained at West Point and some frontier outposts until Congress created the United States Army by their resolution of June 3, 1784.
Planning for the transition to a peacetime force had begun in April 1783 at the request of a congressional committee chaired by Alexander Hamilton.
The commander-in-chief discussed the problem with key officers before
submitting the army's official views on May 2. Significantly, there was a
broad consensus on the basic framework among the officers. Washington's
proposal called for four components: a small regular army, a uniformly
trained and organized militia, a system of arsenals, and a military
academy to train the army's artillery and engineer officers. He wanted
four infantry regiments, each assigned to a specific sector of the
frontier, plus an artillery regiment. His proposed regimental
organizations followed Continental Army patterns but had a provision for
increased strength in the event of war. Washington expected the militia
primarily to provide security for the country at the start of a war
until the regular army could expand—the same role it had carried out in
1775 and 1776. Steuben and Duportail submitted their own proposals to Congress for consideration.
Although Congress declined on May 12 to make a decision on the
peace establishment, it did address the need for some troops to remain
on duty until the British evacuated New York City and several frontier
posts. The delegates told Washington to use men enlisted for fixed terms
as temporary garrisons. A detachment of those men from West Point reoccupied New York without incident on November 25. When Steuben's effort in July to negotiate a transfer of frontier forts with Major General Frederick Haldimand
collapsed, however, the British maintained control over them, as they
would into the 1790s. That failure and the realization that most of the
remaining infantrymen's enlistments were due to expire by June 1784 led
Washington to order Knox, his choice as the commander of the peacetime
army, to discharge all but 500 infantry and 100 artillerymen before
winter set in. The former regrouped as Jackson's Continental Regiment
under Colonel Henry Jackson
of Massachusetts. The single artillery company, New Yorkers under John
Doughty, came from remnants of the second Continental Artillery
Regiment.
Congress issued a proclamation on October 18, 1783, which approved Washington's reductions. On November 2, Washington, then at Rockingham near Rocky Hill, New Jersey, released his Farewell Orders issued to the Armies of the United States of America
to the Philadelphia newspapers for nationwide distribution to the
furloughed men. In the message he thanked the officers and men for their
assistance and reminded them that "the singular interpositions of
Providence in our feeble condition were such, as could scarcely escape
the attention of the most unobserving; while the unparalleled
perseverance of the Armies of the United States, through almost every
possible suffering and discouragement for the space of eight long years,
was little short of a standing Miracle."
Washington believed that the blending of persons from every
colony into "one patriotic band of Brothers" had been a major
accomplishment, and he urged the veterans to continue this devotion in
civilian life.
Washington said farewell to his remaining officers on December 4 at Fraunces Tavern in New York City. On December 23 he appeared in Congress, then sitting at Annapolis, and returned his commission as commander-in-chief:
"Having now finished the work assigned me, I retire from the great
theatre of Action; and bidding an Affectionate farewell to this August
body under whose orders I have so long acted, I here offer my
Commission, and take my leave of all the employments of public life."
Congress ended the War of American Independence on January 14, 1784, by
ratifying the definitive peace treaty that had been signed in Paris on
September 3.
Congress again rejected Washington's concept for a peacetime
force in October 1783. When moderate delegates then offered an
alternative in April 1784 which scaled the projected army down to 900
men in one artillery and three infantry battalions, Congress rejected it
as well, in part because New York feared that men retained from
Massachusetts might take sides in a land dispute between the two states.
Another proposal to retain 350 men and raise 700 new recruits also
failed. On June 2 Congress ordered the discharge of all remaining men
except twenty-five caretakers at Fort Pitt and fifty-five at West Point. The next day it created a peace establishment acceptable to all interests.
The plan required four states to raise 700 men for one year's
service. Congress instructed the Secretary of War to form the troops
into eight infantry and two artillery companies. Pennsylvania, with a
quota of 260 men, had the power to nominate a lieutenant colonel, who
would be the senior officer. New York and Connecticut each were to raise
165 men and nominate a major; the remaining 110 men came from New
Jersey. The economy was the watchword of this proposal, for each major
served as a company commander, and line officers performed all staff
duties except those of chaplain, surgeon, and surgeon's mate. Under Josiah Harmar, the First American Regiment slowly organized and achieved permanent status as an infantry regiment of the new Regular Army. The lineage of the First American Regiment is carried on by the 3rd United States Infantry Regiment (The Old Guard).
However, the United States military realized it needed a well-trained standing army following St. Clair's defeat on November 4, 1791, when a force led by Major General Arthur St. Clair was almost entirely wiped out by the Northwestern Confederacy near Fort Recovery, Ohio. The plans, which were supported by U.S. President George Washington and Henry Knox, Secretary of War,
led to the disbandment of the Continental Army and the creation of the
Legion of the United States. The command would be based on the
18th-century military works of Henry Bouquet, a professional Swiss soldier who served as a colonel in the British Army, and French MarshalMaurice de Saxe. In 1792, Anthony Wayne,
a renowned hero of the American Revolutionary War, was encouraged to
leave retirement and return to active service as Commander-in-Chief of
the Legion with the rank of major general.
The Legion was recruited and raised in Pittsburgh. It was formed into four sub-legions. These were created from elements of the 1st and 2nd Regiments from the Continental Army. These units then became the First and Second Sub-Legions. The Third and Fourth Sub-Legions were raised from further recruits. From June 1792 to November 1792, the Legion was stationed at Fort LaFayette in Pittsburgh.
Throughout the winter of 1792–1793, existing troops along with
new recruits were drilled in military skills, tactics, and discipline at
Legionville on the banks of the Ohio River near present-day Baden, Pennsylvania. The following Spring the newly named Legion of the United States left Legionville for the Northwest Indian War, a struggle between American Indian tribes affiliated with the Northwestern Confederacy in the area south of the Ohio River. The overwhelmingly successful campaign was concluded with the decisive victory at Fallen Timbers
on August 20, 1794, Maj. Gen. Anthony Wayne applied the techniques of
wilderness operations perfected by Sullivan's 1779 expedition against
the Iroquois. The training the troops received at Legionville was also
seen as instrumental to this overwhelming victory.
Nevertheless, Steuben's Blue Book remained the official manual for the legion, as well as for the militia of most states, until Winfield Scott in 1835. In 1796, the United States Army was raised following the discontinuation of the legion of the United States.
Rank insignia
During the American Revolutionary War, the Continental Army initially wore ribbons, cockades, and epaulettes of various colors as an ad hoc form of rank insignia, as General George Washington wrote in 1775:
"As the Continental Army has
unfortunately no uniforms in 1775, and consequently many inconveniences
must arise from not being able to distinguish the commissioned officers
from the privates, it is desired that some badge of distinction be
immediately provided; for instance that the field officers may have red
or pink colored cockades in their hats, the captains yellow or buff, and
the subalterns green."
In 1776, captains were to have buff or white cockades.
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