OF THE UNIVERSE. THE ARABIANS. 221 



alchemistic rules of the Pseudo-Democritus and the Sophist 

 Synesius, or even from Chinese sources through the medium 

 of the Mogols. According to the most recent and very 

 careful investigations of a celebrated orientalist, Reinaud, 

 the invention of gunpowder, ( 348 ) and its application to 

 projectiles, are not to be ascribed to the Arabians : Hassan 

 Al-Rammah, who wrote between 1285 and 1295, was not 

 acquainted with this application; while, as early as th 

 twelfth century, 200 years therefore before Berthold Schwarz, 

 a kind of gunpowder was used at Eammelsberg in the 

 Harz, for blasting rocks. The invention of an air thermo- 

 meter has been ascribed to Avicenna, on the strength of a 

 notice by Sanctorius ; but this notice is very obscure, and 

 six centuries elapsed before Galileo, Cornelius Dreddel, and 

 the Academia del Cimento, by the establishment of an exact 

 measure of temperature, created the important means of 

 penetrating into a world of almost unknown phsenomena, 

 whose regularity and periodicity excite our astonishment; 

 and of recognising the cosmical connection of effects taking 

 place in the atmosphere, in the superimposed aqueous strata 

 of the ocean, and in the interior of the earth. Among the 

 advances which physical science owes to the Arabians, it 

 will be sufficient to name Alhazen's work on the refraction 

 of rays, which may indeed have been partially derived from 

 Ptolemy's optical researches ; and the knowledge and first 

 application of the pendulum as a measure of time ( 349 ) by 

 the great astronomer Ebn- Junis. 



The purity and rarely disturbed transparency of the Arabian 

 sky had in a peculiar manner drawn the attention of the Arab 

 race, in their earliest uncultivated state in their native land, to 

 the motions of the heavenly bodies ; for we find that, besides 



