^2 COSMOS. 



Although the purity and rarely disturbed transparency of 

 Ihe sky of Arabia, must have especially directed the attention 

 of the people, in their early uncultivated condition, to the 

 motions of the stars, as we learn from the fact that the 

 etellar worship of Jupiter, practised under the Lachmites by 

 the race of the Asedites, included Mercury, which, from its 

 proximity to the sun, is less frequently visible ; it would, 

 nevertheless, appear that the remarkable scientific activity 

 manifested by the Arabs in all branches of practical astro- 

 nomy, is to be ascribed less to native than to Chaldean and 



cap. 4), it was an actual astronomical clock, a "horologium ex aqua," a very 

 complicated " machina hydraulica," working by toothed wheels (versatilia 

 tympani deuticuli aequales alius alium impellentes). It is therefore not 

 improbable, that the Arabs who were acquainted with the improved 

 mechanical constructions in use under the Roman empire, may have 

 succeeded in constructing an hydraulic clock with wheel-work, (tympana 

 quse nonnulli rotas appellant, Graeci autam TrepiVoxa. Vitruvius, x. 4.) 

 Leibnitz (Annales Imperil Occidentis Brunsvicenses, ed. Pertz, t. i. 

 1843, p. 247) expresses his admiration of the construction of the clock 

 of Haroun Al-Raschid (Abd-Allatif, trad, par Silvestre de Sacy, p. 578). 

 The piece of mechanism which the Sultan sent from Egypt, in 1232, to 

 the Emperor Frederic II., seems, however, to have been much more 

 remarkable. It was a large tent, in which the sun and moon were 

 moved by mechanism, and made to rise and set, and show the hours of 

 the day and night at correct intervals of time. In the Annales Gode- 

 fridi Monachi S. Pantaleonis apud Coloniam Agrippinam, it is said 

 to have been a " tentorium, in quo imagines solis et lunae artificialiter 

 rnotse cursum suum certis et debitis spaciis peragrant, et horas diei et 

 noctis infallibi liter indicant." (Freheri rerum germanicarum scriptores, 

 t. i. Argentor. 1717, p. 398.) The monk Godefridus, or whoever else 

 may have written the annals of those years in the chronicle composed for 

 the convent of St. Pantaleon at Cologne, which was probably the work 

 of many different authors, (see Bohmer, Fontes rerum germanicarum, 

 bd. ii. 1845, s. xxxiv.-xxxvii.), lived in the time of the great Emperor 

 Frederic II. himself. The emperor caused this curious work, the value 

 of which was estimated at 20,000 marks, to be preserved at Venusium, 

 with other treasures. (Fried, von Raumer, Gesch. der Holienstaufen, 

 bd. iii. s. 430.) That a movement like that of the vault of heaven should 

 have been given to the whole tent, as has often been asserted, appears 

 to me very improbable. In the Chronica Monasterii Hirsaugiensis, 

 edited by Trithemius, we find scarcely anything beyond a mere repe- 

 tition of the passage in the Annales Godefridi, without any information 

 regarding the mechanical construction. (Joh. Triihemii Opera historica, 

 P. ii. Francof. 1601, p. 180.) Reinaud says that the movement waa 

 imparted " par des ressorts cache's." (Extraits des Historiens Ardbes 

 rdati/8 aux guerres des Croisades, 1829, p. 435.) 



