Ikigai Daily
Menu
WonderSurvey history fact

The Great Trigonometrical Survey of India, begun in 1802, found that a Himalayan summit called Peak XV, later named Mount Everest, was the highest mountain then known. Surveyors worked this out by measuring angles from stations on the plains, far from the peak.

Great Trigonometrical Survey

ScienceHistoryEngineering

The story behind the card

The survey was begun by William Lambton, an officer of the East India Company, and took until 1871 to finish; its maps served British rule as well as science. In 1852 the mathematician Radhanath Sikdar, chief 'computer' (the job title for staff who did the calculations) in the survey's Calcutta office, combined six observations of Peak XV and found it to be the highest summit known, at exactly 29,000 feet (8,839 metres). According to the usual account, the surveyor general, Andrew Waugh, added two feet so that the figure would not look like a rounded guess, and announced 29,002 feet in 1856. Waugh proposed naming the peak after his predecessor, George Everest, although Tibetans already called it Chomolungma. Its official height today is 8,848.86 metres.

Türkçe oku
1802'de başlayan Büyük Trigonometrik Ölçüm, Hindistan'ı baştan sona ölçerken, sonradan Everest adını alacak Tepe XV'in o dönem bilinen en yüksek dağ olduğunu ortaya çıkardı. Ölçüm ekipleri bunu dağa hiç yaklaşmadan, ovadaki uzak istasyonlardan açı ölçerek hesapladı.

Ölçümü Doğu Hindistan Şirketi subayı William Lambton başlattı ve iş ancak 1871'de bitti; çıkan haritalar bilimin yanı sıra İngiliz yönetimine de hizmet etti. 1852'de ölçümün Kalküta bürosunda hesapları yöneten matematikçi Radhanath Sikdar, Tepe XV için yapılmış altı ayrı gözlemi birleştirdi ve bu zirvenin bilinen en yüksek dağ olduğunu buldu: tam 29.000 fit, yani 8.839 metre. Anlatılana göre ölçüm şefi Andrew Waugh, bu sayı yuvarlanmış bir tahmin gibi görünmesin diye iki fit ekledi ve 1856'da yüksekliği 29.002 fit olarak duyurdu. Waugh, dağa kendisinden önceki şef George Everest'in adının verilmesini önerdi; oysa Tibetliler dağa çoktan Chomolungma diyordu. Everest'in bugünkü resmî yüksekliği 8.848,86 metredir.

Sources and further reading

Background reading: Great Trigonometrical Survey
Get the mobile appAbout our cards

Related cards

These cards share a subject or reading mode with the card above.

WonderScience

The Struve Geodetic Arc is a 2,820-kilometre chain of survey points running from Norway to the Black Sea. Between 1816 and 1855, surveyors used it to measure a long north-south line across the globe and work out the size and shape of the Earth.

The survey was led by Friedrich Georg Wilhelm Struve, a German-born astronomer who directed the observatory at Dorpat, now Tartu in Estonia, where the chain's first point still stands. It used triangulation: surveyors measured a base line very precisely, then worked out every further distance by measuring the angles between distant hilltops and towers. The finished chain has 258 main triangles and 265 station points, from Hammerfest in Norway to a point near the Black Sea in Ukraine. When it was built it crossed only three states, Norway, Sweden and the Russian Empire; today it crosses ten. The results, published in 1858, put the Earth's flattening at the poles at about 1 part in 294, close to today's figure of 1 in 298. In 2005 UNESCO listed 34 of the station points as a World Heritage Site.

Struve Geodetic ArcRead card
WonderEngineering

Roman concrete has kept harbours, domes and aqueducts standing for 2,000 years, and small white lumps of lime inside it are one reason. When water seeps into a crack, calcium from these lumps can form new crystals that seal it.

For a long time these white lumps, called lime clasts, were taken as a sign of careless mixing. A 2023 study in Science Advances by a team at MIT led by Admir Masic proposed another explanation. The Romans, it argued, added quicklime, a highly reactive form of lime, directly to the mix, where it heats up as it reacts; this method, called hot mixing, left the lumps behind. To test the idea, the team made concrete the same way, cracked it and ran water through the cracks. Within about two weeks the cracks had sealed, while in a sample made without quicklime they did not. Volcanic ash from the Bay of Naples also added strength. A 2017 study of Roman harbour walls, led by the geologist Marie Jackson, found a different process: seawater seeping through them reacts with the volcanic ash and grows rare minerals that reinforce the concrete.

Roman concreteRead card
WonderEngineering

The Tacoma Narrows Bridge in Washington State collapsed on 7 November 1940, four months after opening, when a wind of about 64 km/h set its light, flexible deck twisting until it tore apart. The disaster changed how engineers design long bridges against wind.

The bridge moved so much in the wind from the day it opened that locals nicknamed it Galloping Gertie. On the final morning the motion changed from up-and-down waves to a violent twisting, filmed by a local camera shop owner. No person died; a dog left in a stranded car was lost. The collapse is often blamed on resonance, but engineers now describe it as aeroelastic flutter: the twisting deck and the wind fed energy into each other. The investigation board included the aerodynamicist Theodore von Kármán. The replacement bridge, opened in 1950, used a deep, open truss that lets the wind pass through, and wind-tunnel tests became standard for long bridges.

Tacoma Narrows BridgeRead card
WonderHistory

The 'Three Sisters' are maize, beans and squash, planted together by Indigenous farmers of the Americas so that each crop helps the others grow.

All three crops were first domesticated in Mesoamerica, today's Mexico and Central America: squash about 10,000 years ago, then maize and beans over the following thousands of years. Growing them together later spread across much of North America. Each plant has a job. The maize stalk is a pole for the bean vine to climb; bacteria living in small lumps on the bean roots turn nitrogen from the air into a form plants can use, which enriches the soil; and the broad squash leaves shade the ground, keeping it moist and holding back weeds. Among the Haudenosaunee (Iroquois) of the north-east, the crops appear in stories as three sisters who thrive only together, and a modern experiment found that their traditional mixed planting produced more food energy and protein than any of the crops grown alone.

Smithsonian Folklife FestivalRead card
DriveScience

Srinivasa Ramanujan, a largely self-taught mathematician working as a clerk in Madras, sent the Cambridge mathematician G. H. Hardy a letter full of new results in 1913. A year later he travelled to England to work with Hardy.

Mathematicians in Madras had already recognised his gift and helped him publish and find support before he left India. At Cambridge, working closely with Hardy, Ramanujan produced striking results in number theory, the study of whole numbers, and in infinite series. Hardy later called their collaboration the one romantic incident in his life. Ramanujan was elected a Fellow of the Royal Society in 1918. His health broke down in England, and he returned to India in 1919; he died the following year, aged 32. His notebooks, full of results written down without proof, kept mathematicians busy for decades, and some of his ideas are still being applied today.

History of mathematicsRead card
Next card in the archiveMarie Tharp, an American geologist, drew the first detailed maps of the Atlantic seafloor from ships' depth readings. In the early 1950s she found a deep valley running along the middle of the undersea Mid-Atlantic Ridge, strong evidence that the seafloor is spreading apart.Read next →