Lucien LaCoste
Encyclopedia
Lucien LaCoste was a prominent physicist
, metrologist
. He was coinventor of the modern gravimeter
, invented the zero-length spring, and vehicle-mounted gravimeters. He was also co-founder of a prominent company selling gravimetric instruments.
LaCoste discovered the zero-length spring in 1932 while performing an assignment in Arnold Romberg's undergraduate physics course. A zero-length spring is a spring supported in such a way that its exerted force is proportional to its length, rather than the distance it is compressed. That is, over at least part of its travel, it does not conform to Hooke's Law
of spring compression.
The zero-length spring is extremely important to seismometer
s and gravimeter
s because it permits the design of vertical pendulums with (theoretically) infinite periods. In practice, periods of a thousand seconds are possible, a hundredfold increase from other forms of pendulum.
Over a short period starting in 1932, the design of these instruments was revolutionized, obsoleting all previous designs.
During this period, LaCoste and his physics teacher Arnold Romberg invented the first modern seismographs and gravimeters, using steel and quartz (respectively) zero-length springs.
While a graduate student, LaCoste decided to go into business together with Romberg, selling advanced gravimeters to oil-exploration companies.
LaCoste's most famous invention is the ship, and aircraft-mounted gravimeter. These revolutionized exploration for minerals by allowing wide-ranging geological surveys. The chief problem that Lacoste defeated was to distinguish the accelerations of the vehicles from the accelerations due to gravity, and measure the minute changes in gravity. Since the accelerations from the vehicle typically are hundreds to thousands of times more forceful than the measured changes, this invention was considered impossible until LaCoste demonstrated it.
These inventions give no flavor for LaCoste's fun-loving, often puckish character. These anecdotes were related by one of his many friends, C.R. Dawson.
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
, metrologist
Metrologist
Metrologists perform metrology work involving precision measurement and comparison of physical quantities such as mass, length, time, force, speed, voltage and current. They calibrate precision equipment which measures these physical units. They may also certify that outside standards of such...
. He was coinventor of the modern gravimeter
Gravimeter
A gravimeter or gravitometer is an instrument used in gravimetry for measuring the local gravitational field of the Earth. A gravimeter is a type of accelerometer, specialized for measuring the constant downward acceleration of gravity, which varies by about 0.5% over the surface of the Earth...
, invented the zero-length spring, and vehicle-mounted gravimeters. He was also co-founder of a prominent company selling gravimetric instruments.
LaCoste discovered the zero-length spring in 1932 while performing an assignment in Arnold Romberg's undergraduate physics course. A zero-length spring is a spring supported in such a way that its exerted force is proportional to its length, rather than the distance it is compressed. That is, over at least part of its travel, it does not conform to Hooke's Law
Hooke's law
In mechanics, and physics, Hooke's law of elasticity is an approximation that states that the extension of a spring is in direct proportion with the load applied to it. Many materials obey this law as long as the load does not exceed the material's elastic limit. Materials for which Hooke's law...
of spring compression.
The zero-length spring is extremely important to seismometer
Seismometer
Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...
s and gravimeter
Gravimeter
A gravimeter or gravitometer is an instrument used in gravimetry for measuring the local gravitational field of the Earth. A gravimeter is a type of accelerometer, specialized for measuring the constant downward acceleration of gravity, which varies by about 0.5% over the surface of the Earth...
s because it permits the design of vertical pendulums with (theoretically) infinite periods. In practice, periods of a thousand seconds are possible, a hundredfold increase from other forms of pendulum.
Over a short period starting in 1932, the design of these instruments was revolutionized, obsoleting all previous designs.
During this period, LaCoste and his physics teacher Arnold Romberg invented the first modern seismographs and gravimeters, using steel and quartz (respectively) zero-length springs.
While a graduate student, LaCoste decided to go into business together with Romberg, selling advanced gravimeters to oil-exploration companies.
LaCoste's most famous invention is the ship, and aircraft-mounted gravimeter. These revolutionized exploration for minerals by allowing wide-ranging geological surveys. The chief problem that Lacoste defeated was to distinguish the accelerations of the vehicles from the accelerations due to gravity, and measure the minute changes in gravity. Since the accelerations from the vehicle typically are hundreds to thousands of times more forceful than the measured changes, this invention was considered impossible until LaCoste demonstrated it.
These inventions give no flavor for LaCoste's fun-loving, often puckish character. These anecdotes were related by one of his many friends, C.R. Dawson.
- As a young man, Dr. LaCoste once caused a near-riot in an Austin speakeasySpeakeasyA speakeasy, also called a blind pig or blind tiger, is an establishment that illegally sells alcoholic beverages. Such establishments came into prominence in the United States during the period known as Prohibition...
(a ProhibitionProhibitionProhibition of alcohol, often referred to simply as prohibition, is the practice of prohibiting the manufacture, transportation, import, export, sale, and consumption of alcohol and alcoholic beverages. The term can also apply to the periods in the histories of the countries during which the...
-era illegal bar) by looking up from a book and ordering a glass of milk. - Dr. LaCoste was a fine tennis player. One summer, while he was studying at his family home near Fort Sam Houston in San Antonio, he received a phone call from some friends saying that another friend (later to become one of San Antonio's top surgeons) had just been given a rude and unsporting drubbing in a tennis match at the San Antonio Country Club. LaCoste interrupted his reading, ran the few miles from his house to the country club, handily defeated the offender in straight sets, and ran back home to resume his studies.