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Benvenuti in queste pagine dedicate a scienza, storia ed arte. Amelia Carolina Sparavigna, Torino

Saturday, June 16, 2018

The monk, the polyhedrons and the wardrobe




Fra Giovanni da Verona. Tarsia raffigurante un armadio con poliedri. Courtesy Laurom di Wikipedia in italiano. 

Fra Giovanni da Verona (1457 circa – 1525) è stato un intarsiatore, miniatore, scultore nonché architetto italiano, attivo tra la fine del XV secolo e l'inizio del XVI secolo. Artista poliedrico, è ricordato in particolare per la maestria nell'intarsio e nella prospettiva.

Sfere cinesi (puzzle spheres)



Sfera cinese, in avorio, fatta di diverse sfere concentriche (British Museum. Original photograph from Ged Carroll)


Wikipedia dice che questo tipo di lavori è diventato popolare in Europa grazie alla produzione Cinese del XIX secolo. Ma la creazione di questi rompicapo ha origini ben più lontane. Antikitera.net ci informa che i primi esemplari fecero la loro comparsa durante la Dinastia Song, intorno all'anno 1000 d.C.

Pierre MEYER and the puzzle dodecahedron



Pierre Meyer is an artist who works with ivory.

A puzzle ball




Puzzle ball. This image is a courtesy of   " The Puzzle Museum http://puzzlemuseum.org". 

Chinese and European ivory puzzle balls

"By the 18th century China had a considerable market in items such as figures made for export to Europe, and from the Meiji Period Japan followed. Japanese ivory for the domestic market had traditionally mostly been small objects such as netsuke, for which ivory was used from the 17th century, or little inlays for sword-fittings and the like, but in the later 19th century, using African ivory, pieces became as large as the material would allow, and carved with virtuosic skill. A speciality was round puzzle balls of openwork that contained a series of smaller balls, freely rotating, inside them, a tribute to the patience of Asian craftsmen."

Usually, many of these balls have a decorated stand made of ivory too.



Chinese puzzle ball, with openwork and a series of twelve smaller balls, ivory, 19th century. British Museum. Original photograph from Ged Carroll

"Originally, they (Chinese puzzle balls) were made almost exclusively from ivory, or the tusks of elephants and were the playthings of rich men because of the time and effort involved in making them. ... Usually, puzzle balls are symbols of good luck, and are decorated with a variety of feng shui symbols. The outermost layer often features the phoenix and dragon, symbols of yin and yang. The phoenix represents the wife while the dragon is the husband and emperor, and balls decorated with these symbols are thought to bring good luck and happiness to a marriage. In fact, almost all of the symbols most commonly associated with puzzle balls are associated with ensuring a long and happy marriage. Some balls even have different symbols on different layers, though the most common is a highly decorative outer ball and ‘latticed’ balls inside (with geometric patterns of holes)."



Detail of an ivory ball on show in the German Rautenstrauch-Joest Museum. It has 16 layers, which can spin. Courtesy Till Niermann , Wikipedia.


In the above image we see an example of Canton ivory carving. From Wikipedia (on the Lingnan culture or Cantonese culture). "Canton ivory woodcarving is another well-known product from Lingnan. With a history of 2000 years, it traditionally uses ivory as raw material to make sculptures, with the Canton-style renowned for being particularly delicate and detailed without being brittle. The Cantonese people have also successfully produced the legendary craft product - Ivory ball. After the 1980s, however, international ivory trade has been banned. This results in the Cantonese people now trying to find substitute materials - materials that look and feel like but are actually not ivory - in their attempt to pass on this ancient art."

"Chinese puzzle balls are ornate decorative items that consist of several concentric spheres, each of which rotates freely, carved from the same piece of material. ... These detailed works of art are usually made up of at least 3 to 7 layers, but the world’s largest puzzle ball is actually made of 42 concentric balls all enclosed one within the other. Although the inner balls can be manipulated to align all the holes, Chinese puzzle balls got their name from people who, through the ages, pondered the mystery of making such objects. So how exactly are puzzle balls made? .... Chinese masters rotate a solid ball on a lathe and start by drilling holes toward the center of the objects. Then, using special “L”-shaped tools, they begin to separate the innermost balls. ...  Because it is easier to work with, the exterior shell is the most elaborately carved, usually featuring an intertwined dragon and a phoenix."

Antikitera.net tells us that the first puzzle balls appeared during the Song Dynasty, around 1000 d.C.
http://www.antikitera.net/news.asp?ID=11753

After having shown the Chinese ivory balls, it seems that the puzzle balls became popular in Europe thanks to Chinese products of the later XIXth century. However, puzzle balls existed in Europe in XVI or XVII century. Here an example.



European puzzle ball, XVI-XVII Century (Image Courtesy: Maureen and Renato Bucci, Italy). It was exhibited with a rosary having the beads made in the same manner of the ball. 



The rosary, XVI-XVII Century (Image Courtesy: Maureen and Renato Bucci, Italy).  


The ball shown in the image is remarkable because it looks like a Roman Dodecahedron. Actually Renato Bucci was so kind to send me the picture because of this similarity. Probably, this was an object of a Wunderkammer (in italiano, camera delle meraviglie o gabinetto delle curiosità o delle meraviglie), encyclopedic collections of objects of the Reinassance Europe.  


"The Kunstkammer was regarded as a microcosm or theater of the world, and a memory theater. The Kunstkammer conveyed symbolically the patron's control of the world through its indoor, microscopic reproduction."


An example of Kunstkammer
http://wonder-cabinet.sites.gettysburg.edu/2017/cabinet/carved-ivory-puzzle-balls/


Besides the balls, we have also the polyhedra. Here the dodecahedra created by Egidius Lobenigk (1581 - 1584). From https://artsandculture.google.com/entity/m0t50361?categoryid=artist we can see them. 



These dodecahedra are at Staatliche Kunstsammlungen Dresden, (courtesy image from Jürgen Karpinski, photographer).

Let me conclude remarking that today puzzle balls are created too. Here the image of one of them, which is showing a contempoary "puzzle dodecahedra". The artist that created it is Pierre Meyer is an artist who works with ivory. https://www.maitresdart.com/pierre_meyer-40/parcours_et_realisations.html



Pierre Meyer's ivory "puzzle dodecahedron".


Also "new production of ornamental turning ivory of '600" is evidenced by the works of Andrea Pacciani, architect in Parma, by the web https://www.etsy.com/it/listing/225172225/tornitura-ornamentale-da-un-modello-in. A piece "is inspired by a piece of the museum's collection of Rosenborg in Denmark (*). Another piece is inspiered to the drawings of Grollier de Serviere, (1596–1689), French inventor and ornamental turner.
According to Andrea, "Thanks to the new generation of 3D technologies we could bring back the light of contemporary production about this object collection of great visual impact". That is, new technologies for creating objecs for our modern Wunderkammer.


(*) the reader can see the pieces at http://www.bobkatsjaunt.com/denmark.html.





A drawing from a book on the works of  Grollier de Serviere

Friday, June 15, 2018

La fragole di Sophia

Ho trovato questo articolo, molto bello.

Sofia e la scoperta delle fragole, di Marco Bersanelli
"Il valore dell'ipotesi positiva nella ricerca scientifica. L'imprevisto, un avvenimento che porta a una novità irriducibile al già noto. L'adeguatezza della realtà all'io"
http://diesselombardia.vigevano.biz/imgdb/Scopertascientifica1997.pdf

Wednesday, June 6, 2018

Marc Antony's speech

Friends, Romans, countrymen, lend me your ears;
I come to bury Caesar, not to praise him. The evil that men do lives after them;
The good is oft interred with their bones; So let it be with Caesar.
The noble Brutus Hath told you Caesar was ambitious:
If it were so, it was a grievous fault, And grievously hath Caesar answer’d it.
Here, under leave of Brutus and the rest – For Brutus is an honourable man;
So are they all, all honourable men – Come I to speak in Caesar’s funeral.
He was my friend, faithful and just to me: But Brutus says he was ambitious;
And Brutus is an honourable man.
He hath brought many captives home to Rome Whose ransoms did the general coffers fill: Did this in Caesar seem ambitious? When that the poor have cried, Caesar hath wept: Ambition should be made of sterner stuff:
Yet Brutus says he was ambitious; And Brutus is an honourable man.
You all did see that on the Lupercal I thrice presented him a kingly crown,
Which he did thrice refuse: was this ambition? Yet Brutus says he was ambitious;
And, sure, he is an honourable man.
I speak not to disprove what Brutus spoke, But here I am to speak what I do know.
You all did love him once, not without cause: What cause withholds you then, to mourn for him?
O judgment! thou art fled to brutish beasts, And men have lost their reason. Bear with me;
My heart is in the coffin there with Caesar, And I must pause till it come back to me.




Arcobaleno

Torino, ore 6:30, 6 Giugno 2018



Monday, June 4, 2018

The Elephant - the symbol of the Caesar family

Gaius Julius Caesar (12 or 13 July 100 BC – 15 March 44 BC) is known by his cognomen Julius Caesar. Caesar was born into the gens Julia, descent from Iulus, son of Aeneas. The family originated from Alba Longa. The cognomen "Caesar" originated, according to Pliny the Elder,  with an ancestor who was born by Caesarean section. The Historia Augusta suggests three possbile explanation: that the first Caesar had a thick head of hair (Latin caesaries); that he had bright grey eyes (Latin oculis caesiis); or that he killed an elephant (caesai in Moorish) in battle. Caesar issued coins featuring images of elephants, suggesting that he favored this interpretation of his name.

Silver Denarius - Military mint in Italy, circa 49 B.C. Elephant walking right, trampling on serpent, CAESAR in exergue. Sacrificial implements, simpulum, sprinkler, axe and priest's hat. 
The obverse type may symbolize victory over evil, whereas the reverse refers to Caesar's office of Pontifex Maximus.


 

Sunday, May 13, 2018

I Menhir di Sorgono (Biru e Concas) e le stelle

 Fig.1

Nel cuore della Sardegna, quasi al suo centro geografico (Fig.1), si trovano i menhir di Biru 'e Concas. L'importante sito archeologico è situato nel territorio del comune di Sorgono, in provincia di Nuoro. Wikipedia ci dice che il sito, che sorge su una collina, era probabilmente dedicato ad antenati defunti, diventati eroi della popolazione locale. Il sito risale ad un periodo compreso tra il Neolitico Recente (3300-2700 a.C.) e l'Eneolitico (2700-1700). I menhir si trovano disposti in molti modi, anche in allineamenti. Alcuni menhir presentano delle forme antropomorfe, e sono quindi definiti come statue stele. In Sardegna, le statue stele vengono datate intorno al III millennio a.C. (età del rame) e si possono suddividere in due tipi figurativi: un tipo maschile, che probabilmente rappresentava eroi o guerrieri mitici, ed un tipo con attributi femminili. 


Fig.2: Un allineamento del sito di Biru e Concas (Cortesia, Alberto Zilaghe, Street View, Google Earth)

Del sito di Biru 'e Concas, un articolo di Antonella Petris su meteoweb.eu riporta quanto segue. "Come spiega Corrado Mascia, un lettore di Meteoweb che di recente ha avuto modo di osservarli, “la concentrazione dei menhir è straordinaria ...  Sono disposti in coppia, isolati o in triadi secondo allineamenti circolari estesi che possono comprendere fino a venti menhir. Consistono, dunque, in un complesso di allineamenti megalitici, che secondo un filone culturale di studiosi, costituivano le carte astronomiche (o osservatori astronomici)determinanti il tempo e lo spazio e capaci di segnare i solstizi e gli equinozi". 


Fig.3: Ecco un notevole allineamento di 20 menhir. Seguono la direzione cardinale Nord-Sud.
In figura (Cortesia, SunCalc.org) si vedono le direzioni del sorgere del sole e del tramonto all'equinozio, secondo un orizzonte astronomico. L'allineamento di menhir è coincidente con la direzione meridiana.

Fig.4: Un altro allineamento di menhir (deviazione di circa 10 gradi dalla direzione cardinale verso Sud).


Consideriamo  il primo allineamento di menhir, quello che ha la direzione Nord-Sud. Se  guardiamo  verso Sud,  utilizzando Google Earth e il suo strumento che permette di avere il profilo di elevazione locale, vediamo che l'orizzonte naturale si eleva di circa 4 o 5 gradi sopra l'orizzonte astronomico. 
Che stelle potevano vedere le persone che avevano costruito il sito?
Usiamo il software Stellarium, che ci permette di simulare il cielo antico (Fig.5 e 6).


Fig.5: Ecco le stelle che si potevano vedere guardando verso Sud attorno al 3300 BC. Sopra l'orizzonte naturale, rappresentato dalla linea arancione, splende la Croce del Sud. Anche Alpha Centauri (Rigil Kentaurus) è visibile. La linea bianca rappresenta l'orizzonte astronomico.


Fig.6: Per effetto della precessione dell'asse terreste, attorno al 1700 BC, le stelle della Croce sono più basse sull'orizzonte naturale. 

Guardando la Fig.6, ci possiamo chiedere: Rigil Kentaurus era visibile sopra l'orizzonte naturale? Ed eventualmente, in che direzione sorgeva? Proviamo a simulare come si poteva vedere sorgere Rigil Kentaurus al sito di Sorgono (Fig.7). 

 Fig.7

Sempre con Stellarium, abbiamo che Rigil Kent arrivava a circa 4 gradi sull'orizzonte astronomico, e quindi poteva esser vista sorgere dall'orizzonte naturale, quanto il suo azimuth era di 10 gradi circa rispetto al Sud. Ma questo angolo è proprio l'angolo del secondo allineamento, quello mostrato nella Fig.4. 

In effetti, quanto detto dall'articolo di meteoweb.eu è ben fondato. Sarebbe interessante aver a disposizione altri articoli che mostrino anche gli allineamenti dei menhir, oltre a quelli che si vedono nelle'immagini satellitari, per poter fare altre simulazioni e conseguenti paragoni con le mappe stellari.