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



Pliny, in "one of the most remarkable literary produc- 

 tions in the domain of geology" (Zittel). 



With the fall of Rome and the decline of Roman civ- 

 ilization came a period of intellectual darkness, from 

 which the world did not emerge until the revival of learn- 

 ing in the fifteenth and sixteenth centuries. Then the 

 extension of geographical knowledge went hand in hand 

 with the development of art, literature, and the birth of a 

 new science. Copernicus (1473-1543) gave the world at 

 last a sun-controlled solar system; Kepler (1571-1630) 

 formulated the laws governing the motion of the planets ; 

 Galileo (1564-1642) with his telescope opened up new 

 vistas of astronomical knowledge and laid the founda- 

 tions of mechanics; while Leonardo da Vinci (1452-1519), 

 painter, sculptor, architect, engineer, musician and true 

 scientist, studied the laws of falling bodies and solved 

 the riddle of the fossils in the rocks. Still later Newton 

 (1642-1727) established the law of gravitation, developed 

 the calculus, put mechanics upon a solid basis and also 

 worked out the properties of lenses and prisms so that 

 his Optics (1704) will always have a prominent place in 

 the history of science. 



From the time of the Renaissance on science grew 

 steadily, but it was not till the latter half of the eight- 

 eenth century that the foundations in most of the lines 

 recognized to-day were fully laid. Much of what was 

 accomplished then is, at least, outlined in the chapters 

 following. 



Our standpoint in the early years of the nineteenth 

 century, just before the American Journal had its begin- 

 ning, may be briefly summarized as follows : A desire 

 for knowledge was almost universal and, therefore, also 

 a general interest in the development of science. Mathe- 

 matics was firmly established and the mathematical side 

 of astronomy and natural philosophy — as physics was 

 then called — was well developed. Many of the phenom- 

 ena of heat and their applications, as in the steam engine 

 of Watt, were known and even the true nature of heat had 

 been almost established by our countryman, Count Rum- 

 ford ; but of electricity there were only a few sparks of 

 knowledge. Chemistry had had its foundation firmly 

 laid by Priestley, Lavoisier, and Dalton, while Berzelius 

 was pushing rapidly forward. Geology had also its 

 roots down, chiefly through the work of Hufcton and 



