Per Theodor

DeLange, Titia (1998). Telomeres and Senescence. Science 279 334-335. Felsenfeld, Gary (1985). DNA. Scientific American 253(4) 58-67. 

McCarty, MacLyn (1985). The Transforming Principle Discovering That Genes Are Made of DNA. New York Norton. 

Robert (1998). Bacterial Gene Swapping in Namre. Scientific American 278(1) 67-71. 

Neufeld, Peter, and Coknan, NeviUe (1990). When Science Takes the Witness Stand. Scientific American 262(5) 46-53. 

Per Theodor Cleve was a nineteenth-centuiy expert in agricultural chemistry, inorganic and organic chemistries, geology, mineralogy, and oceanography. 

---

Per Theodor Cleve (1840-1905) independently Marc Delafontaine (1837-1911) and J.-L. Soret (1827-1890). 

Helium - the atomic number is 2 and the chemical symbol is He. The name derives from the Greek helios for sun . The element was discovered by spectroscopy during a solar eclipse in the sun s chromosphere by the French astronomer Pierre-Jules-Cesar Janssen in 1868. It was independently discovered and named helium by the English astronomer Joseph Norman Lockyer. It was thought to be only a solar constituent until it was later found to be identical to the helium in the uranium ore cleveite by the Scottish chemist William Ramsay in 1895. Ramsay originally called his gas krypton, until it was identified as helium. The Swedish chemists Per Theodore Cleve and Nils Abraham Langet independently found helium in cleveite at about the same time. 

Holmium - the atomic number is 67 and the chemical symbol is Ho. The name derives from the Latin holmia for Stockholm . It was discovered in erbia earth by the Swiss chemist J. L. Soret in 1878, who referred to it as element X. It was later independently discovered by the Swedish chemist Per Theodor Cleve in 1879. It was first isolated in 1911 by Holmberg, who proposed the name holmium either to recognize the discoverer Per Cleve, who was from Stockholm or perhaps to establish his own name in history. 

Scandium - the atomic number is 21 and the chemical symbol is Sc. The name derives from the Latin scandia for Scandinavia , where the mineral were found. It was discovered by the Swedish chemist Lars-Fredrik Nilson in 1879 from an ytterbium sample. In the same year, the Swedish chemist Per Theodore Cleve proved that scandium was Mendeleev s hypothetical element eka-boron , whose properties and position in the Period Table Mendeleev had previously predicted. 

It was not until 1895 that Scottish chemist Sir William Ramsay (1852-1916) first found hehum on Earth when he experimented with uranium and subsequently coUected the gases that were produced when he treated his samples with acid. He sent the gases to Sir William Crookes (1832—1919), who identified one gas as hehum. Two Swedish chemists, Per Theodor Cleve... 

In 1879 holmium was discovered, independently, by Per Theodor Cleve (1840—1905), who managed to isolate holmium from the other rare-earths. Cleve received credit for the discovery of holmium and named it for the Latin word holmia, which means Stockholm, a city in his native country, Sweden. 

In the meantime Per Theodor Cleve, tire Swedish chemist for whom the mineral cleveite had been named by its discoverer, A. E. Nordenskiold, had his student Nils Abraham Langlet investigate it (53). Although Ramsay announced the discovery before Cleve and Langlet had completed their research, the Swedish chemists were independent discoverers of helium. Langlet s first helium was purer, in fact, than Ramsay s, for he obtained a much better value for its atomic weight (13, 31, 32). The spectroscopic measurements were made by Professor Robeit Thaten (47). 

Thulium Tm 69 Per Theodor Cleve Sweden "Thule", an ancient name for Scandinavia... 

Four rare-earth elements (yttrium, ytterbium, erbium, and terbium) have been named in honor of this village. A year later, the Swedish chemist Lars Fredrik Nilson (1840-1899), discovered another element in "erbia" and he named it scandium (Sc) in honor of Scandinavia. At the same time, Nilson s compatriot, the geologist and chemist Per Theodor Cleve (1840-1905) succeeded in resolving the "erbia" earths yet another step further, when he separated it into three components erbium, "holmium" (Flo) and thulium (Tm). The name "holmium" refers to Stockholm (Qeve s native city) and had been independently discovered by the Swiss chemists Marc Dela-fontame (1838-1911) and Jacques-Louis Soret (1827-1890), who had coined the metal element X on the basis of its absorption spectrum. 

Chemiluminescence, 403 Citric acid method, 396, 400 Cleve, Per Theodor, 8 Closed-packed fullerenes, 136 Cluster, 138 beam, 97... 

The name is from the Latin Holmia for the city of Stockholm, the region where the original minerals were found. The discovery of holmium was part of the complex yttria rare-earths research. A new element was suggested by Jacques-Louis Soret (1827-1890) in 1878 and was named by Per Theodor Cleve (1840-1905) in 1880 its oxide was isolated in 1886 by Lecoq de Boisbaudran. The pure metal was isolated in 1911 by 0. Holmberg. It is a rare element and does not occur in pure form in nature. The silvery metal has unusual magnetic properties but no current commercial uses. 

The element is named after Thule, the ancient name for Scandinavia. It is part of the yttria rare earths and is about as abundant as silver or cadmium. It was discovered in 1879 by Per Theodor Cleve. The silvery metallic element does not occur in elemental form naturally. It is very expensive and has few commercial uses, although synthetic radioactive isotopes have been used as an X-ray source. 

In 1904 Ramsay received the Nobel Prize in chemistry in recognition of his services in the discovery of the inert gaseous elements in air, and his determination of their place in the periodic system, becoming the first British recipient of this award, see also Argon Cleve, Per Theodor Strutt, John (Lord Rayleigh). 

Thulium is a silver-grey metal with a bright luster. Swedish chemist Per Theodor Cleve discovered the metal in 1879 while processing the ore er-bia. One of the materials Cleve extracted from the ore was a green substance he named thulia —a thulium oxide. The element s name is derived from an ancient name for northern Europe, Thule. 

Thulium metal is soft, ductile, and malleable and can be cut with a knife. It tarnishes when in contact with air and reacts with water. Thuhum has very few commercial uses. Radioactive thulium can be utihzed as a power source for portable x-ray machines and is produced by irradiating the element in a nuclear reactor. Thulium may also be utihzed to make magnetic ceramic materials found in microwave equipment, see also Cleve, Per Theodore. 

---