ILLUSTKATIONS 



PAGE 



BARON ALEXANDER VON IITJMBOLDT Frontispiece 



HUMPHRY DAVY 3 



JOSIAH WEDGWOOD 6 



HERSCHEL AND HIS SISTER AT THE TELESCOPE 9 



JAMES LOUIS LAGRANGE 14 



JAMES HUTTON 18 



BENJAMIN THOMPSON COUNT RUMFORD 25 



JOSKPH PRIESTLY 30 



LAVOISIER IN HIS LABORATORY . ' 37 



EDWARD JENNER . 41 



FUIEDRICH WILHELM BESSEL 45 



HEINKICH WILHELM MATTHIAS OLBERS 55 



SIR JOHN HERSCHEL 61 



THE GREAT REFRACTOR OF THE NATIONAL OBSERVATORY AT 



WASHINGTON 67 



A TYPICAL STAR CLUSTER CENTAURI 71 



SPECTRA OF STARS IN CARINA 73 



STAR SPECTRA 75 



LORD ROSSE'S TELESCOPE 77 



NO. 1 SIDEREAL TIME, 15 HOURS, 50 MINUTES ) 



NO. 2 SIDEREAL TIME, 17 HOURS, 50 MINUTES I 



THE OXFORD HELIOMETER 85 



GEORGES CUVIER 92 



THE WARREN MASTODON, FOUND NEAR NEWBURG, ON THE 



HUDSON 94 



V 



