ILLUSTRATIONS 



PAGE 



BARON ALEXANDER VON HUMBOLDT Frontispiece 



HUMPHRY DAVY 3 



JOSIAH WEDGWOOD 6 



HERSCHEL AND HIS SISTER AT THE TELESCOPE 9 



JAMES LOUIS LAGRANGE 14 



JAMES BUTTON 18 



' 



BENJAMIN THOMPSON COUNT RUMFORD 25 



JOSKPH PRIESTLY 30 



LAVOISIER IN HIS LABORATORY 37 



EDWARD JENNER 41 



FKIEDKICH WILHELM BESSEL 45 



HEINRICH 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 ) 



THE OXFORD HELIOMETER 85 



GEORGES CUVIER 92 



THE WARREN MASTODON, FOUND NEAR NEWBURG, ON THE 



HUDSON 94 



V 



