Will 



GENERAL SUMMARY OF SCIENTIFIC AND 



The accounts of the recent Indian eclipse (December 11, 

 1871) arc as yet very meagre, and do not indicate that any 

 thing has been done beyond confirming the former discover- 

 Ii is said that the spectroscope has indicated the exist- 

 ence of water at a great height above the sun, but this was 

 done by Professor Winlock, in Spain, in 1870. It is also said 

 that the reversal of the bright lines seen by Professor Young 

 has been confirmed. 



Intimately connected with the question of the- corona and 

 protuberances is that of the temperature of the sun, to which 

 an impulse has been given by the researches of Pere Secchi. 

 Starting from the observed rise of temperature produced by 

 the solar rays, this eminent physicist computed that the tem- 

 perature of the incandescent surface of the sun could not be 

 less than 10,000,000 degrees ! The French physicists, start- 

 ing from the very same data, find a temperature of only a 

 Jew thousand degrees no higher, in fact, than what can be 

 produced by artificial means at the surface ofthe earth. The 

 difference arises from the difference of the supposed law of 

 increase of radiation with the temperature. Pere Secchi sup- 

 poses the radiation to be exactly proportional to the temper- 

 ature, an hypothesis contradicted by experiment; while the 

 French start from the law of Dulong and Petit, which is 

 founded on actual observations. They have, therefore, the 

 best of the argument. 



The return of two periodic comets, those of Encke and Tut- 

 tlc, <luring the year, has led to a complete confirmation of the 

 observations made in previous years with the spectroscope 

 on other comets, namely, that these bodies give a spectrum 

 of bright lines, like glowing gas, and very closely resembling 

 that of defiant gas. But no one has yet explained how a red- 

 hot gas can move through the planetary spaces without either 

 cooling off or expanding indefinitely by its own elastic force, 

 so that, in fact, this discovery has left the exact nature of 

 comets a greater mystery than ever. The spectroscope has 

 also revealed atmospheres of great absorbing power around 

 tin' planets Uranus and Neptune. It is not found possible to 

 identify them with any known terrestrial substance, but it 

 ins not unlikely that carbonic acid is an important con- 

 stituent. 



There is now some prospect that American astronomers 



