18 COSMOS. 



in which he exults in having discovered 400 hitherto unob- 

 served stars in a space of one or two degrees. He never 

 makes any reference to unresolved nebulous matter. Yet 

 how could the great nebulous spot in the sword of Orion have 

 failed to rivet his attention ? But, although this great ob- 

 server probably never saw the irregular nebula in Orion, or 

 the roundish disk of a so-called irresolvable nebula, sdfl his 

 general views^ on the intrinsic nature of nebulous spots were 

 very similar to those to which the greater number of our 

 astronomers of the present day incline. Like Galileo, Hevel 

 of Daritzig, who, although a distinguished observer, was not 

 much inclined to rely upon telescopic observation for aid in 

 cataloguing the stars,! made no mention in his writings of 

 the great nebula in Orion. His star catalogue, moreover, did 

 not contain upward of 16 nebulous spots, of which the posi- 

 tions were accurately determined. 



At length, in the year 1656, Huygens discovered the neb- 



* " In primo integram Oriouis constellationem pingere decreveram ; 

 vero, ab ingenti stellarum copia, temporis vero inopia obrutus, aggres- 

 siouem hauc in aliam occasionem distuli. Cum nou tautum in Galaxia 

 Lacteus ille candor veluti albicantis nubis spectetur, sed complures con- 

 similis coloris areolte sparsimper &thera subfulgeajit, si in illarum, quam- 

 libet epecillurn couvertas, stellarum constipatarum coetum offendes. 

 Amplius (quod magis mirabile) stellse, ab astronomis singulis in hanc 

 usque diem nebulosa appellate, stellarum minim in rnodum consitarum 

 gregessunt : ex quarum radiorum commixtione, dum uuaquaque ob ex- 

 ilitatem, seu maximam a nobis retnotiouem, oculorura aciem i'ugit, can- 

 dor ille consurgit, qui densior pars coeli, stellarum aut solis radios re- 

 torquere valens, hucusque creditus est." Opere di Galileo Galilei, Pa- 

 dova, 1744, torn, ii., p. 14, 15. " At first I had resolved to describe 

 the whole constellation of Orion ; but the multitude of the stars and the 

 want of leisure compelled me to postpone the undertaking till another 

 occasion. Since not only in the Milky Way may be observed that brill- 

 iancy as of a whitish cloud, but several areoles of a similar color are 

 scattered through the firmament ; if you direct the glass to any one of 

 them, you will meet with a host of clustered stars. Moreover, the stars 

 (still stranger to say) which, by every astronomer, are to this day call- 

 ed nebulous, are clusters of stars lying close together in a wonderful 

 manner, from the combination of whose rays (while they can not be 

 separately distinguished by the eye on account of their minuteness, or 

 their very great distance from us) arises that whiteness, which, from its 

 capacity of reflecting the rays of the stars or of the sun, has been hith- 

 erto supposed to belong to a denser part of the atmosphere." Side- 

 revs Nuntiut, p.* 13, 15 (Nos. 19-21), and 35 (No. 56). 



t Compare Cosmos, vol. iii., p. 41. I also remember a vignette at the 

 close of the introduction to Hevel's Firmamentiim Sobescianum, 1687, 

 in which three genii are represented, two of whom are making ob 

 servations with Hevel's sextants. The third genius is carrying a tele- 

 scope which he appears to be worshiping, while those observing ex- 

 claim, Pr<sstat nudo oculo ! 



