Dana — American Journal of Science, 1818-1918. 3 



that down to the time with which we are immediately con- 

 cerned, it was the branches of mathematics, as arithmetic 

 and geometry and later their applications, that were first 

 and most fully developed : in other words those lines of 

 science least closely connected with nature. 



Of the importance to science of the Greek school at 

 Alexandria in the second and third centuries B. C, there 

 can be no question. The geometry of Euclid (about 300 

 B. C.) was marvelous in its completeness as in clearness 

 of logical method. Hipparchus (about 160-125 B. C.) 

 gave the world the elements of trigonometry and devel- 

 oped astronomy so that Ptolemy 260 years later was able 

 to construct a system that was well-developed, though in 

 error in the fundamental idea as to the relative position 

 of the earth. It is interesting to note that the Almagest 

 of Ptolemy was thought worthy of republication by the 

 Carnegie Institution only a year or two since. This 

 great astronomical work, by the way, had no successor 

 till that of the Arab Ulugh Bey in the fifteenth century, 

 which within a few months has also been made available 

 by the same Institution. 



To the Alexandrian school also belongs Archimedes 

 (287-212 B. C), who, as every school boy knows, was the 

 founder of mechanics and in fact almost a modern physi- 

 cal experimenter. He invented the water screw for rais- 

 ing water; he discovered the principle of the lever, 

 which appealed so keenly to his imagination that he 

 called for a -n-ov o-™, or fulcrum, on which to place it so as 

 to move the earth itself. He was still nearer to modern 

 physics in his reputed plan of burning up a hostile fleet 

 by converging the sun's rays by a system of great 

 mirrors. 



To the Romans, science owes little beyond what is 

 implied in their vast architectural monuments, buildings 

 and aqueducts which were erected at home and in the 

 countries of their conquests. The elder Pliny (23-79 

 A. D.) most nearly deserved to be called a man of science, 

 but his work on natural history, comprised in thirty- 

 seven volumes, is hardly more than a compilation of 

 fable, fact, and fancy, and is sometimes termed a collec- 

 tion of anecdotes. He lost his life in the "grandest 

 geological event of antiquity," the eruption of Vesuvius, 

 which is vividly described by his nephew, the younger 



