20 H. A. LENEHAN. 
A brief statement, and especially a numerical statement, of this 
kind should not be criticised too closely in detail ; but it may be 
accepted unhesitatingly as giving a general idea of the situation. 
Professor E. E. Barnard, who has had probably more experience 
of the largest telescopes in favourable conditions than any one, 
is of opinion that the naked eye view of the moon better 
represents the view of Mars through the best telescope.” 
Professor W. H. Pickering states that on examining a 
number of photographs of Mars, which were secured with 
the 11-inch Draper telescope during March 31st to 
April 30th, 1905, it was seen that no snow-caps properly 
so-called appeared until April 23rd. The photograph of 
March 31st showed clouds on both the terminator and the 
limb, but no polar caps. On April 23rd, a clearly visible 
and extensive light area appeared at the southern pole, 
but was not bright enough for snow, rather resembling an 
extensive region of clouds. A very small light area 
appeared near to the northern pole on April 15th, but was 
only seen with difficulty; a visual examination with a 
24-inch reflector revealed the southern polar cap on 
April 30th, as extending far towards the north in 
longitude 340. Professor Pickering thinks that when 
the clouds disperse snow will probably be revealed lying 
in their place. He also contends that the observed 
seasonal coJour, changed from brown to green, on such 
features as the Mare Erythrzeum is the surest evidence of 
the existence of vegetation on Mars. 
Sixth Satellite of Jupiter.—This new satellite was 
discovered while observations were being made with the 
36-inch Crossley reflector at the Lick Observatory during 
December 1904, and was confirmed by further observations 
on January 4th, 1905. Perrine, the discoverer, states 
that its distance from the planet on the latter date was 
45 so that it is situated at a cousiderably greater distance 
