XII List of Plates. 



Facing page. 

 S3. Thomas Say (1787-1834), naturalist. From an engraving by Hoppner 



Meyer of a painting by Wood 398 



84. Henry Rowe Schoolcraft ( 1 793-1 864), naturalist and explorer. From an 



engraving by Illman and Sons 402 



85. Pietro Angelo Secchi ( 1818-1878) , astronomer. From a wood cut 406 



86. Benjamin Silliman (1779-1S64), chemist. From a mezzotint by P. N. 



Whclpley 410 



87. Sir Hans Sloane (1660-1752), founder of British Museum. From a steel 



engraving 4^4 



88. James Edward Smith (1759-1S28), botanical writer. From a photograph 



of an engraving 418 



89. John Smith ( 1579-1632), English explorer. PVom an engraving 422 



90. Jakob Steendam (1616-1662), poet and naturalist. From a lithograph of 



a steel engraving 426 



91. Isaac Ingalls Stevens (1818-1862), army explorer. From an engraving 



by J. C. Buttre 430 



92. Isaiah Thomas (1749-1831), founder of the Antiquarian Society in 



Worcester, Mass. From an engraving by J. R. Smith 434 



93. Benjamin Thompson, Count Rumford (1753-1814), chemist and physi- 



cist. From an engraving by T. Mviller 438 



94. John Torrey ( 1 796-1873), botanist. From a lithograph 442 



95. John Tradescant (1608-1662), traveler and naturalist. From a reproduc- 



tion of an old engraving 446 



96. Gerard Troost (1776-1850), mineralogist and geologist. From a steel 



engraving 450 



97. William Petit Trowbridge (1828-1S92), civil and mechanical engineer. 



From a photograph 454 



98. Stephen Van Rensselaer (1765-1S39), founder of the Van Rensselaer 



Polytechnic Institute. From an engraving by G. Parker of a minia- 

 ture by C. Eraser 458 



99. Garcilaso de la Vega (1539-1616), Peruvian historian. From an early 



engraving by Carmona 462 



100. Benjamin Waterhouse (1754- 1846), physician. From an engraving by 



R. Reeve 466 



loi. Francis Wayland (1796-1865), president of Brown University. From an 



engraving by J. C. Buttre 470 



102. David Ames Wells (1828-1S98), political economist. From an engraving 



by H. W. vSmith 474 



103. William Dvvight Whitney (1827-1S94), philologist. From an engraving 



by J. C. Buttre 478 



104. Charles Wilkes (1798-1877), naval explorer. From an engraving by 



A. H. Ritchie 482 



105. Hugh Williamson (1735-1819), promoter of scientific enterprises. From 



an etching by Albert Rosenthal of a painting by J. Trumbull 486 



106. Alexander Wilson (1766-1813), ornithologist. From an old engraving. . 490 



107. Caspar Wistar (1761-1818), professor of anatomy. From an engraving 



by J. B Longacre of a painting by B. Otis 494 



108. Jeffries Wyman (1814-1S74), comparative anatomist. From an engrav- 



ing b}' L,. S. Punderson 498 



109. Edward Livingston Youmans (1821-1887), founder of Popular Science 



Monthly. From an engraving by C. Schlecht 500 



