ASTRONOMICAL PHENOMENA AND PROGRESS. 



53 



light was brightest at the less refrangible end, 

 and gradually diminished toward the other 

 limit of the bands. The least refrangible of the 

 three bands did not exhibit a similar gradation 

 of brightness. These bands could not be re- 

 solved into lines, nor was any light seen be- 

 yond the. bands toward the violet and the red. 

 The author found this cometic spectrum to 

 agree exactly with a form of the spectrum of 

 carbon which he had observed and measured 

 in 1864. When an induction spark, with Ley- 

 den jars intercalated, is taken in a current of 

 olefiant gas, the highly heated vapor of carbon 

 exhibits a spectrum which is somewhat modi- 

 fied from that which may be regarded as typical 

 of carbon. The light is of the same refrangi- 

 bility, but the separate strong lines are not to 

 be distinguished. The shading, composed of 

 numerous fine lines, which accompanies the 

 lines, appears as an unresolved nebulous light. 

 On June 23d the spectrum of the comet was 

 compared directly in the spectroscope with the 

 spectrum of the induction spark taken in a 

 current of olefiant gas. The three bands of 

 the comet appeared to coincide with the corre- 

 sponding bands of the spectrum of carbon. In 

 addition to an apparent identity of position, 

 the bands in the two spectra were very similar 

 in their general characters and in their rela- 

 tive brightness. These observations were con- 

 firmed on June 25th. 



The remarkably close resemblance of the 

 spectrum of the comet to that of the spec- 

 trum of carbon necessarily suggests the identity 

 of the substances by which in both cases the 

 light was emitted. The great fixity of carbon 

 seems, indeed, to raise some difficulty in the 

 way of accepting the apparently obvious infer- 

 ence from these prismatic observations. Some 

 comets have approached sufficiently near the 

 sun to acquire a temperature high enough to 

 convert even carbon into vapor. In the case 

 of other comets, the author suggests that the 

 difficulty is one of degree only, for the condi- 

 tions are not known under which even a gas 

 permanent, at the temperature of the earth, 

 could maintain sufficient heat to emit light. 

 The spectrum shows that the .color of this 

 comet was bluish green. Considerable differ- 

 ence of color has been remarked in the parts 

 of some comets. Sir William Herschel de- 

 scribed the head of the comet of 1811 to be of 

 a greenish or bluish-green color, while the 

 central point appeared of a ruddy tint. The 

 same colors have been observed, in other 

 comets. If carbon be the substance of some 

 comets, this substance, if incandescent in the 

 solid state, or reflecting when in a condition 

 of minute division, the light of the sun, would 

 afford a light which, in comparison with that 

 emitted by the luminous vapor of carbon, 

 would appear yellowish or approaching to red. 

 The author refers to the bearing of these re- 

 sults on certain cometary phenomena, and on 

 the apparent identity of the orbits of the peri- 

 odical meteors with those of some comets. 



The Colors of Saturn. Mr. John Browning 

 has sent to the /Student a report of his recent 

 observations of the colors of Saturn. Examin- 

 ing the planet at midnight, May 9th, with a 12- 

 inch instrument and a power of 100, he found 

 no perceptible color. Under a power of 200 

 to 450, the ring appeared lemon-yellow ; the 

 globe, light cinnamon with darker belts scarce- 

 ly of the same color ; Ball's division, purple- 

 chocolate ; crape ring, same color ; pole of the 

 planet, bright azure. May 14th he took another 

 set of observations. The definition was much 

 better than on the 9th, but the colors were 

 not nearly so vivid as on the former date. 

 The north pole of the globe was neutral gray 

 and darker than any other part of the planet, 

 excepting the broad reddish-brown belt imme- 

 diately north of the equatorial white belt. No 

 part of the globe was pure white. The author 

 remarks that with a 12-inch silvered glass 

 mirror, and a power of 500, the whole ring 

 system produces the impression that it consists 

 of fine lines. Slight inequalities may sometimes 

 be detected in the belts of the globe ; more 

 generally they appear quite regular, like the 

 rim of a wheel in rapid motion. 



Mr. Huggins hearing that Mr. Browning was 

 engaged on this subject, sent him notes of some 

 of his own observations of Saturn. Mr. H. 

 says that though he can see the colors of Sat- 

 urn fairly with powers of 500 or 600, yet he 

 finds a power of, at least, 900 necessary to 

 bring out the contrast of the colors in the full- 

 est manner. He warns inexperienced observers 

 that, in consequence of the small altitudes of 

 Saturn, there are prismatic colors seen on it, 

 produced by our atmosphere. From this cause 

 red is seen along the upper edge of the planet 

 in an inverting telescope, and a strong blue at 

 the lower or north edge of the ring, and at the 

 pole. Some time ago, he had considered the 

 crape ring to be of the color of watch-spring ; - 

 lately he has regarded it as rather more of a 

 grayish blue. Mr. Browning remarks upon 

 this, that the color of the crape ring will vary 

 greatly with the state of an atmosphere. 

 When there is much mist in the air, the color 

 will incline toward red ; when the air is clear, 

 the color will become a purer blue. 



The author thinks that the different tints on 

 different portions of the rings may be ascribed 

 to the unequal distribution of the countless 

 multitude of minute satellites of which the 

 rings are supposed to be made up. The pres- 

 ence of an atmosphere may further modify 

 their colors. That the rings have an atmosphere, 

 he regards as pretty certain, from the appear- 

 ance they present when their edges are turned 

 toward us. At such times, nebulous append- 

 ages like clouds have been seen upon them. 

 The surface of the globe of Saturn may have a 

 soil of the color of new red sandstone. This 

 color would certainly be strongly modified by 

 cloud-belts, which exist principally at the 

 equator, but extend to the poles. The poles 

 may consist of masses of ice ; but it is difficult 



