Wyniki wyszukiwania - Biblioteka Nauki

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ON WITELO'S DIFFRACTION OF SUNLIGHT IN A CRYSTAL

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Burchardt J.

Analecta. Studia i Materiały z Dziejów Nauki

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2006

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tom 15

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nr 1-2(29-30)

199-205

EN

Around the year 1270, Witelo, a son of 'Thuringians and Poles' who originated from Poland, diffracted beams of sunlight into colours in a transparent hexagonal crystal. The main goal of the current paper is to show the way in which Witelo systematically came closer to making his discovery, which took place at Viterbo, through proofs contained in Books Two and Ten of his major work entitled 'Perspectiva', written in 1271. The original Latin text of Witelo's optical discovery from the manuscript held at Cambridge, Emmanuel College Library 20, has been published in the journal 'Organon', 33 (2004), in the notes on pp. 76-80.

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RELATIONS BETWEEN DUKE WLODZISLAW AND WITELO

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Burchardt J.

Analecta. Studia i Materiały z Dziejów Nauki

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2006

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tom 15

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nr 1-2(29-30)

159-167

EN

Peter Lombard's 'Sententiae' of the 12th century contained rigorous rules on the ordination of priests, which were followed by popes. The regulations also concerned the Piast Duke of Wroclaw and Archbishop of Salzburg, Wlodzislaw, as well as his peer from the time of their studies at the faculty of liberal arts at Paris, master Witelo. The current paper deals with the relations between Duke Wlodzislaw and Witelo. It also presents the whole of the duke's life and, in the case of Witelo, gives a detailed account of the period of his studies. Details of Witelo's later life are presented in a book by the author of the article, entitled 'Witelo filosofo dalla natura del XIII sec. Una Biografia', Wroclaw 1984.

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Elementy wkładu Arabów do farmakognozji średniowiecza łacińskiego

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Burchardt J.

Kwartalnik Historii Nauki i Techniki

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2001

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tom R. 46, nr 2

7--34

EN

Most of the pharmacognosy in the Latin Middle Ages (11 th-15th centuries), just like almost all of the medical knowledge of that period, emerged in the course o f translation of medical treatises written in the Arabic language and script. For instance, the views of the great Graeco-Roman physician Galen were arranged into a homogenous system by Hunain ibn Ishak, an authority on the medical treatises by Galen; because o f the fact that Latin Europe learnt about it from the arabie version, this system is now referred to as Arabic Galenism. The Latin translations o f the pharmacognostic treatises of Pseudo- Mesue (10th century) and Pseudo-Serapio (13th century) introduced Europe to new medications, unknown to Dioscurides in the 1st century AD or Galen in the 2nd century AD. Among these drugs were: alkanet (Lawsonia inermis L.), Socotran aloe (Aloe poeryi Baker and A. Socotrina L.), alunite, then called Yemeni alum (alumen iameninum), Meccan bdellium (gum resin o f Hyphaena thebaica Mart., Arecaceae), gum arabie (from Acacia tortilis Hayne, Mimosaceae), myrrh (gum resin from the tree Commiphora abysinnica Engler, Burseraceae), the fruit of barberry (Berberis vulgaris L., Berberidaceae), borage (Borago officinalis L., Boraginaceae), ambergris (the fragrant substance from the digestive tract o f the sperm whale, Physeter macrocephalus L.), Borneo camphor or bomeol (plates or follicles under the bark of the Indonesian and Indian tree Dryobalanops aromatica Gaertn., Diperocarpacceae), cassia pods (pods of Cassia fistula L., Caesalpiniaceae), and cassia bark extracted from among the many varietes of Greek cassia (the bark of the cinammon-like Cinnamonum cassia Blume, Lauraceae). The Arabs’ exports to Europe includes grains of the cubeb pepper (Piper cubeba L., Piperaceae), mace (nutmeg aril osnowka muszkatołowa) and nux muscata (nutmeg) from the nutmeg tree (Myristica fragrans Houtt., Myristiceae), Meccan senna (sene, the leaves of Cassia angustifolia Vahl., Caesalpiniaceae) turpeth (the root of Iopomoea turpethum R. Brown, Convolvulaceae), ginger (zinziber, Zingiber officinale Roscoe, Zingiberaceae) and cane sugar (zuccarum, Saccharum officinarum L., Poaceae) a preservative of compound drugs.

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PHANTASMS OF FIGURES AT DAWN AND DUSK ACCORDING TO WITELO

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Burchardt J.

Analecta. Studia i Materiały z Dziejów Nauki

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2008

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tom 17

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nr 1-2(33-34)

7-14

EN

The author takes up the topic of optical illusions and their mental interpretation by sighted people. The basis for the study is provided by an analysis of examples in Book IV of Witelo's 'Perspectiva' and his philosophical letter to Ludwig at Lwówek Slaski (Loewenberg). The 13th-century Silesian scholar based his theory on the ideas of Ibn al-Haitham (Alhazen), an optician, astronomer, catoptrician and mathematician active in Egypt in the first half of the 11th century. Witelo interpreted the figures of demons that thrived in the minds of his contemporaries as optical illusions transformed by the imagination. The notion of phantasms, figures appearing as result of optical conditions at dawn and dusk, is an original term of Witelo's and, until today, his only precise one - it refers to true figures completely transformed by human imagination. Witelo gives examples of real human and animal figures that have undergone multiple enhancement in the eyes of those who perceive them, due to the optical conditions that obtain at the time. The use of Witelo's term, 'phantasms', was later abandoned. The basis for all further interpretation of the phenomenon is provided by Witelo's geometric theorem from Book IV of his 'Perspectiva': 'All things viewed at the same angle, unless and until their distance (from the observer) is investigated, appear equal'. The interpretation of such phenomena by Witelo was quite novel in the late Middle Ages and in a way it heralded the coming of a new epoch in the history of human thought.