176 
doctrines among the Greeks and Hindoos, appear remarkable, 
the absence among both, of the same sciences, is not less so. 
Thus, though the Hindoos, like the Egyptians, must have 
been acquainted with many mechanical powers, they do 
not seem to have cultivated mechanics as a science ; nor 
hydrostatics, though, like the Chinese, they employed 
clepsydrae for the measurement of time. Neither though 
they knew that air was the vehicle of sound, do they seem 
to have studied its other properties ; nor, though they had 
mirrors, and acquainted as they were with the fact of the 
angle of incidence being equal to the angle of reflection, 
do they seem to have made any further advance in optics. 
But neither was any great progress made in these sciences 
among the Greeks until later ages, as those of Archimedes 
and Ptolemy.* If the Hindoos, therefore, borrowed from 
the Greeks, they must have done so previous to these times, 
of 200 B.C. and 150 A.D. In the same way we have 
inferred, that if they borrowed medicine, they must have 
done so before the time of Galen ; and therefore about the 
period when the peripatetic sages of Greece themselves 
* This may be seen by consulting the valuable work of Mr. Whewell, on 
the History of the Inductive Sciences, which having appeared since the 
Lecture, of which this is a continuation, was delivered, and the greater 
portion of the foregoing pages printed, I have not been able to make the 
use of that I could have wished. I am pleased to find that, though inclined to 
the opinion of the early efforts in physical speculations, and their philosophy 
on such subjects, being the native growth of the Greek mind, and owing 
" nothing to the supposed lore of Egypt and the East ; an opinion which 
has been adopted with regard to the Greek philosophy in general by the 
most competent judges, on a full survey of the evidence,"— he yet makes an 
exception, "perhaps of the Indians, as the only one of the African or Asiatic 
nations, who ever felt the importunate curiosity with regard to the definite 
application of the idea of cause and effect to visible phcenomena." p. 32. 
But that the Greeks received their first impulse in some of these studies 
from without, is shown in a subsequent page, (161,) where a quotation is 
made from Plato ; where, after speaking of the Egyptians and Syrians as 
the original cultivators of astronomical studies, he adds, " Whatever we 
Greeks receive from the barbarians, we improve and perfect." 
