ib 4 IN STARRY REALMS. 



perihelion and receiving a larger supply of sun heat, the 

 meteorological condition of its surface may be very dif- 

 ferent from what is found when the opposition occurs at 

 a different part of the planet's orbit. Still, it is so im- 

 portant to study the aspect of Mars when the north pole 

 is tilted into view, that, notwithstanding the small appa- 

 rent size of the planet when near its aphelion, such oppo- 

 sitions merit careful attention. 



A careful study of Mars was made during the opposition 

 of the planet, in 1884, by Mr. E. B. Knobel, and his 

 drawings are given in Vol. xlviii. of the Memoirs of 

 the Royal Astronomical Society. Although I do not 

 reproduce Mr. KnobePs careful examination of many 

 isolated features on Mars, I give here an abstract of 

 the more general remarks on the planet to which his 

 researches have conducted him. It is impossible to look 

 with care at any of the good drawings of the planet and 

 not be struck with the fact that there is a wide discrepancy 

 between the appearances of the northern and of the 

 southern hemispheres. The various dark markings, the 

 so-called seas, which are so conspicuous and so well 

 marked in the southern hemisphere, become replaced in 

 the northern hemisphere by objects of a much more ambi- 

 guous character. Indeed, the only object in the northern 

 hemisphere which can be regarded as thoroughly marked 

 and identified is that portion of the so-called "Kaiser Sea'* 

 which extends north of the equator. This remarkable 

 Martial feature is by far the most conspicuous and well- 

 defined marking that its globe presents. Even in quite 

 small telescopes the Kaiser Sea is well seen when hardly 

 any other object of the planet admits of being recognised. 



