580 coswns. 



distilled mercury from cinnabar, from the Arabian chemist, 

 Dscheber ; how widely is Ptolemy, as an optician, removed 

 from Alhazen ; but we must, nevertheless, date the founda- 

 tion of the physical sciences, and even of natural science, from 

 the point where new paths were first trodden by many dif- 

 ferent investigators, although with unequal success. To the 

 mere contemplation of nature, to the observation of the 

 phenomena accidentally presented to the eye in the terresr 

 trial and celestial regions of space, succeeds investigation 

 into the actual, an estimate by the measurement of magnitudes 

 and the duration of motion. The earliest epoch of such a spe- 

 cies of natural observation, although principally limited to 

 organic substances, was the age of Aristotle. There remains 

 a third and higher stage in the progressive advancement of 

 the knowledge of physical phenomena, which embraces 

 an investigation into natural forces and the powers by 

 which these forces are enabled to act, in order to be able to 

 bring the substances liberated into new combinations. The 

 means by which this liberation is effected are experiments, 

 by which phenomena may be called forth at will. 



This last-named stage of the process of knowledge, which 

 was almost wholly disregarded in antiquity, was raised by 

 the Arabs to a high degree of development. This people 

 belonged to a country which enjoyed, throughout its whole 

 extent, the climate of the region of palms, and in its greater 

 part that of tropical lands, (the tropic of Cancer intersecting 

 the peninsula in the direction of a line running from Maskat 

 to Mecca,) and this portion of the world was, therefore, cha- 

 racterized by the highly developed vital force pervading vege-. 

 tation, by which an abundance of aromatic and balsamic 

 juices was yielded to man from various beneficial and dele- 

 terious vegetable substances. The attention of the people 

 must early have been directed to the natural products of their 

 native soil, and those brought as articles of commerce from 

 the accessible coasts of Malabar, Ceylon, and Eastern Africa. 

 In these regions of the Torrid Zone, organic forms become 

 individualized within very limited portions of space, each one 

 being characterised by individual products, and thus increas- 

 ing the communion of men with nature, by a constant 

 excitement towards natural observation. Hence arose the 

 wish to iistinguish carefully from one another these preckn$ 



