for the year 1866. 127 



rays pass tlirough space without loss, and only become 

 developed as heat as they enter onr atmosphere, the density 

 and humidity of which govern the amount developed. Such 

 being the case, it does not seem improbable that, however 

 distant a planet may be from the sun — whether near or far 

 — whether it be Mercury or ISTeptune, it receives the same 

 amount of heat as the Earth, the character of their envelop- 

 ing atmospheres entirely governing the supply. The 

 researches of Messrs. Huggins and Thompson, and Father 

 Secchi in Florence, on the spectra of the heavenly bodies, 

 have also ripened into most interesting results. The 

 examination of several of the nebulse by Mr. Huggins with 

 the spectroscope has led to the opinion that they are 

 " gaseous masses," giving light of similar refrangibility to 

 that of nitrogen. A similar examination of Jupiter has led 

 Father Secchi to the impression that his atmosphere has a 

 far higher light-absorbing power than that of the Earth. 

 He thus advances towards the proof required to what I have 

 just mentioned concerning heat-rays traversing space with- 

 out loss, and that the planets probably have atmospheres so 

 constituted, according to their position in space, as to render 

 the light and heat received in some degree equal for all. 

 Through the application of spectrum-analysis to the planets, 

 stars, nebul83, and comets, we are led to believe that many 

 of our views concerning their condition will need consider- 

 able modification. It has generally been believed that the 

 moon possessed no atmosphere ; all evidence pointed always 

 to that conclusion. Mr. Huggins, however, has observed that 

 the spectrum of a fixed star undergoes a change at the moment 

 before occultation by the dark limb of the moon characteristic 

 of the passage of the star's light through an atmosphere. 



Mr. Sorby has much improved on his method of spectrum- 

 analysis by the microscope, and has successfully applied it 

 to the detection of blood-stains. 



