3i8 



SCIENCE. 



with the three lines in the middle band of the carbon 

 spectrum. 



This resolution into lines was seen by Professor 

 Brackett, as well as by Mr. McNeill and myself, on 

 June 29th ; it was still evident on July 2d, but no 

 longer on July 3d. 



The coincidence with the middle band of the flame 

 spectrum,has always appeared to be precise ; but to 

 obtain further evidence as to the exact position of the 

 banc 1 a careful comparison was made on July 2 with 

 the b lines of the magnesium spectrum, using the 

 Grubb spectroscope with a dispersive power of four 

 sixty-degree-dense flint prisms and a magnifying power 

 of about 25. The slit was opened until the well de- 

 fined upper edge of b just touched the lower edge of 

 b 3 . Then, the spark producing the magnesium spec- 

 trum being suppressed, the bright wire of the microme- 

 ter was set upon the lower edge of the comet band ; 

 finally, the spark being restored, the distance was 

 measured from the edges of bi. In this way twelve 

 readings were obtained by Mr. McNeill and myself, 

 all giving results ranging between 5160.0 and 5169.5, 

 the mean being 5164.8 ±-0.7. I do not think the 

 possible error can exceed 2 divisions, or three times 

 the probable error. If so, the Comet spectrum can- 

 not possibly be identified with the second Carbon spec- 

 trum, (the spark spectrum of a Geissler tube contain- 1 

 ing CO). Since the corresponding band of that spec- 

 trum has a wave-length of 5198.4. The wave-length 

 of the band in the flame spectrum is 5165.3 — both 

 according to the figures of Dr. Marshall Watts, given 

 in Nature, vol. 20, page 28. 



As a further test, on July 3d, the suggestion of Dr 

 Watts, made in the paper referred to, was followed out 

 by confronting the comet-spectrum by means of an 

 occulting bar, directly with Geissler tubes containing 

 CO and COs, and with the Bunsen-burner flame. The 

 bands on this night were more distinctly defined than 

 on previous occasions, though the nucleus spectrum 

 was less brilliant, and the result of the confrontal was 

 very satisfactory and decisive. The upper and mid- 

 dle bands were found undoubtedly coincident, so far 

 as the power used could show, with the flame spec- 

 trum, and not with the bands of the tube spectra. In 

 the case of the lower band, the evidence was less con- 

 clusive, because the edge was ill defined and faint, 

 making pointing difficult, and because bands of the 

 flame and tube spectra are nearly coincident here. 

 Still, even with this band, the evidence of about half 

 a dozen pointings turned in the same direction. 



On the whole, I consider it now absolutely certain, 

 that the comet-spectrum is not the second spectrum 

 of Carbon, whether it be the first or not. As to this 

 latter point I do not feel quite sure, but the coinci- 

 dences are certainly very remarkable and close, 



hough the peculiar appearance of the upper and 

 lower bands when the comet was brightest requires 

 explanation. C. A. Young. 



Princeton, July 4, 1881 



PRIMORDIAL COSMIC RINGS. 

 III. 



By Edgar L. Larkin. 



The doctrine that a sphere of atoms, abandoned rings, 

 or any other shaped masses can develop into planets is a 

 physical error. It is impossible that the ball revolved. 

 Face the south, hold the plane of the page of "Science" 

 horizontally, call the paper the centre of the sphere, and 

 it will be seen that to cause rotation, force must be ap- 

 plied, if above the centre, from west to east ; below, from 

 east to west ; to the right, from below, upward ; and to 

 the left, from above, downward. The gas was of ex- 

 cessive tenuity, and external force instead of causing ro- 

 tary motion would displace the atoms in front of it. The 

 mildest, or most violent force alike, would be unable to 

 cause revolution in a globe of atoms of such extreme 

 mobility. But there was no external force ; energy is a 

 property of matter, and the nearest matter was 20 trill- 

 ions of miles away. If the sphere rotated the motion 

 came from internal causes, none of which could have 

 at that time existed. There were no vortices, currents, 

 tides or whirlwinds in matter of such rarity ; no force 

 outside, and none within save the slowest possible radial 

 descent. The sphere was at rest. No point in the ex- 

 periment of M. Plateau had analogy to the generation of 

 rings on the gaseous globe. He placed a globule of oil 

 in a fluid having like specific gravity, passed a wire 

 through it, and turned it as an axis until the sphere of 

 oil partook of the rotation, flattened and detached a ring. 

 The cosmical mass was of rare gas, and existed in a 

 void, with no external power to turn it. If Plateau had 

 suspended a ball of hydrogen in a vacuum, annihilated 

 the attraction of the earth, and then made it revolve 

 without applying force, the cases would be similar. 



Neglecting the laws of Nature we will assume that the 

 primitive sphere was in rotation. Admitting it, a de- 

 monstration will be made that if by unknown law it cast 

 off a ring or any other form of mass, said portion could 

 not have been abandoned anywhere in the vicinity of the 

 orbit of Neptune. 



First proposition : — If the sphere by rotary motion, or 

 other mode of force cast off its equator, matter which 

 condensing made Neptune, then that planet formed, and 

 now moves on a line that coincided with the Centre 

 of Gravity of the discarded mass, no matter what was its 

 shape, size or density. 



This statement we deem self-evident, incapable of ar- 

 gument, and an absolute truth. 



Second proposition : — If the ring that contained the 

 matter now existing in Neptune, was thrown off the 

 equator of a sphere, a section of the ring perpendicular 

 to its length would be either a circle, or a segment of a 

 circle. That is, the ring would be either cylindrical, or flat 

 inside and curved outside, the curvature being the arc of a 

 great circle, a meridian bisecting the poles of the sphere. 

 We can conceive of no form of mass capable of being 

 detached from the circumference of a sphere, other than 

 cylindric or segmental. 



Thiid proposition: — If the Neptunian ring was not 

 cast off when the mass was a sphere, it was abandoned 

 after the ball had depressed at the poles, and elongated 

 at the equator. And a perpendicular section of such de- 

 tached protuberance would be some one of the Conic 

 Sections. 



Draw a chord' of an arc from north to south any dis- 

 tance below the orbit of Neptune, so that it does not de» 



