STEPHEN ALEXANDER. 509 



Laplace's nebular hypothesis had a great fascination for Professor 

 Alexander, and lay at the foundation of most of his astronomical 

 speculations ; although, as in the case just mentioned, he sometimes 

 reached conclusions apparently much at variance with it. He was 

 never weary of speculatioiis bearing upon the origin and structure of 

 the solar system, — the relations between the distances, dimensions, 

 masses, and characteristics of the planets. His most extensive, and 

 undoubtedly, in his own estimate, his most valuable and important 

 work, was "The Plarmonies of the Solar System," published in 1875, 

 as one of the Smithsonian Contributions to Knowledge. In this 

 treatise he considered that he had established the existence of certain 

 determining ratios in the spacing of the planetary orbits, and in their 

 satellite systems. The method, tone, and spirit of the work are essen- 

 tially that of Kepler, rather than that of Galileo or Newton, and quite 

 justifies the title of "the American Kepler" conferred upon him by 

 a foreign critic. 



Numerous other minor papers, containing observations of occulta- 

 tions, longitude determinations, discussions of the asteroid system, etc., 

 are scattered through the Proceedings of the American Philosophical 

 Society, the volumes of Silliman's Journal, Gould's Astronomical 

 Journal, the Astronomische Nachrichten, and other scientific serials. 

 I have not been able to form anything like a complete catalogue of 

 them in the time at my command. The published papers of Professor 

 Alexander are, however, very few compared with the total number 

 of those which he presented at the meetings of the different scientific 

 organizations to which he belonged. He was a ready and fluent 

 speaker, easily presenting his subject from mere skeleton notes; but, 

 like some of the rest of us, he was very impatient of the dull labor of 

 writing necessary to prepare his matter for the press. 



As a scholar Professor Alexander was unusally broad and thorough. 

 He was an excellent linguist, familiar with Greek, Latin, and Hebrew, 

 and well versed in the principal European languages, — at least suffi- 

 ciently so to be able to read any of them except Russian with ease, 

 and to speak and write some of them. He was fond of general litera- 

 ture, of history, fiction, eloquence, and poetry, and himself sometimes 

 wrote verses of no mean order. He was a lover of metaphysics, phi- 

 losophy, and theology, and delighted in controversial debate. He was 

 familiar, of course, with the ordinary literature of his departments 

 of instruction, with Laplace's Mecanique Celeste and many other 

 of his mathematical writings, and with the works of Newton, Euler, 

 and Lagrange. He always also kept up with current mathematical 



