ASTRONOMY AND METEOROLOGY. 323 



nomenon would be explained by the assumption that small in- 

 tensely io:nited bodies are movino; near the sun's surface and 

 sending out rays of all refrangibilities. As the images pass rap- 

 idly before the slit of the spectroscope they give a spectrum with 

 flashing lines. — American Journal of Science and Arts, Nov., 1869. 



ZOLLNER's REVERSION SPECTROSCOPE. 



An important addition to the resources of spectrum analysis 

 has been made by Zollner's invention of a reversion spectroscope, 

 by which extremely small changes in refrangibility, and conse- 

 quently comparatively slow motions of a star or sun-flame can be 

 detected. It consists of a spectroscope in which by reflection the 

 spectrum of a source of light can be superposed above a reversed 

 spectrum of the same source ; so that if a white flame containing 

 sodium be viewed, there will be seen in the upper part of the held 

 a sodium line with the blue end of the spectrum on the one side, 

 and und(!rneath it a sodium line with the red end of the spectrum 

 on the same side. The two bright lines may be made to coincide 

 exactly by an adjustment; and if any change in refrangibility 

 takes place, the motion of the line is doubled, and is also more 

 exactly measured, because it is referred to itself as a standard. — 

 Comptes Rendus. 



ASTRONOMY. 



Mr. Kincaid suggests an ingenious mode of constructing an 

 automatic transit instrument. The apparatus consists of a j^lane 

 mirror, and burning-glass, to be adjusted in such a manner that, 

 at the instant the sun reaches the meridian, the raj's ignite a 

 thread which burns without smoke or residue ; this releases a 

 detent, and a motion is thereby given to the hands of the clock, 

 bringing it to the correct local mean time. Tiiere is a supple- 

 mentary arrangement by which, if the thread should not ignite in 

 consequence of a passing cloud at the instant of the transit of the 

 first limb, the subsequent ignition of the thread will not aflect the 

 clock, Mr. Lockyer, in a note on Mr. Huggins' paper "On a 

 possible Method of viewing Red Flames without an Eclipse," 

 writes to show that he was not aided by the eclipse observations 

 in seeking for the prominence spectrum. Unless Mr. Lockyer 

 claims credit for the discovery of the gaseity of the prominences, 

 apart from the credit due him for his share in the discovery that 

 their spectrum can be seen without an eclipse, we cannot see 

 how Mr. Huggins' mistake (assuming it to be such) at all aftVcts 

 the proper apportionment of recognition in the matter of recent 

 solar discoveries. The eclipse observers clearly deserve all the 

 credit due to the first-mentioned discovery, which had l)een fully 

 discussed in EnoJand for two months before Mr. Lockver exam- 

 ined the prominence spectra. It is impossible to undiscover the 

 discovered. On the other hand, no one has disputed the 



