November 22, 1894] 



NATURE 



87 



dry months of August and September in the villages on the 

 lower slopes of the mountain, gradually creep up the precipitous 

 cliffs from tuft lo tuft of dried herbage till they gain the grassy 

 table-lands, and raging over the plain eat their way along the 

 edges of the remaining belts of forest ; annually scorching, if not 

 burning, the bark and timber of the outside trees, and killing 

 outright the young seedlings. In exceptionally dry seasons 

 even the damper gorges are invaded, and Mr. Whyte describes 

 hundreds of giant trees lying prostrate and piled on each other 

 in all stages of destruction. We are glad to learn that Mr. 

 Johnston, under whose directions Mr. Whyte's exploration was 

 made, has taken steps to prevent a recurrence of such disasters. 



M'idiiriitgtonia zohytei promises to be of great economic value 

 from the excellent quality of its timber for building purposes 

 and furniture. It is easily worked, and is moreover a tree of 

 rapid growth, for Mr. Whyte tells us that in a plantation which 

 he has formed near the residency at Zomba, three-year-old 

 seedlings have already reached a height of ten feet. 



Seeds of the nev/ conifer, forwarded by Mr. Whyte, reached 

 this country in 1S93, and healthy seedlings have been raised 

 in the Royal Gardens, Kew ; in the Botanical Gardens, Edin- 

 burgh ; in Messrs, Veitch's Nurseries ; and in the Zoological 

 Society's Gardens ; so that we may hope to see this fine tree 

 ultimately established in Europe. 



The existence of a large cedar-like tree on Milanji was first 

 discovered by the Rev. Robert Acland, of the Blanlyre Mission, 

 who visited the mountain in 1889 for the purpose of fou'-ding a 

 Mission Station. In Mr. Buchanan's narrative of his journey 

 along the southern frontier of Nyasaland (Proc. R. Geogr. Soc. 

 1891, p. 271) it will be found alluded to as "a species of pine- 

 tree " existing in the ravines on the north-eastern slope. In the 

 latter part of 1891, Dr. W. A. Scott and Mr. Henry Brown 

 made the first ascent of Milanji, going up the southern face, and 

 ascertained the existence of large forests of the so-called 

 " pine" at an altitude of 6000 feet above sea-level. A month 

 later Mr. Whyte succeeded in ascending to the trees, and, as 

 already stated, obtained the first specimens which reached this 

 country, and enabled the tree to be classified and described. 



When Fort Lister was founded in 1893, the cedar forests were 

 found to come down to a much lower altitude on the north-east 

 slopes of Mt. Milanji, and .idvantage was at once taken 

 of this to procure a supply of the timber. It was cut up on the 

 spot, and the planks carried to Zomba, where they have been 

 employed for many purposes. When the residency at Zomba was 

 re-roofed with iron this timber was used for the woodwork. 

 There can be, therefore, no question about the value of this 

 discovery. 



SCHIAPARELLI ON MARS. 



'T'HE following extracts from a translation communicated to 



■*■ Astronomy and Aitro-Phyiics, by Prof. W. H. Pickering, 



I "^ of special interest at the present time, for they set forth 



' . hiaparelli's observations of the planet Mars, and show his 



■ "'ews on various Martian phenomena. The original article was 



contributed by this keen observer to Nalitra cd Arte. 



The Polar Caps. 

 j Many of the first astronomers who studied Mars with the 

 I telescope, noted on the outline of its disc two brilliant white 

 spots of rounded form and of variable size. In process of time 

 it was observed that whilst the ordinary spots upon Mars were dis- 

 placed rapidly in const ijuence of the planet's daily rotation, chang- 

 ing in a few hours both their position and their perspective, that 

 the two white spots remained sensibly motionless at their posts. 

 It was concluded rightly from this, that they must occupy the 

 poles of rotation of ihe planet, or at least must be found very 

 near to them. Consequently they were given the name of 

 polar caps or spots. And not without reason is it conjectured, 

 that these represent upon Mars an immense mass of snow and ice, 

 iinilar to that which today prevents navigators from reaching the 

 I' lies of the Earth. We are led to this conclusion not only 

 l>y the analogy of aspect and of place, but also by another im- 

 j'"rtant observation. 



As things stand, it is manifest, that if the while polar spots of 

 M.xrs represent snow and ice, they should continue to decrease 

 111 size with the appro.ich of summer in those places, and in- 

 crease during the winter. Now this very fact is observed in the 

 most evident manner. In the second half of the year 1892 the 

 southern polar cap was in full view ; during that interval, and 

 especially in the months of July and August, its rapid diminu- 



NO. 1308, VOL. 5 l] 



tion from week to wee'K was very evident, even to those 

 observing with -common telescopes. This snow (for we may 

 well call it so), which in the beginning reached as far as 

 latitude -}o\ and formed a cap of over 2000 kilometres (1200 

 miles) in diameter, progressively diminished, so that two or 

 three months later little more of it remained than an area of 

 perhaps 300 kilometres (180 miles), at the most, and still less 

 was seen later in the last days of 1892.' In these months the 

 southern hemisphere of Mars had its summer ; the summer 

 solstice occurring upon October 13. Correspondingly the mass 

 of snow surrounding the northern pole should have increased ; 

 but this fact was not observable, since that pole was situated in 

 Ihe hemisphere of Mars which was opposite to that facing the 

 Earth. The melting of the northern snow was seen in its turn 

 in the years 1SS2, 1884, and 1886, 



The southern snow, however, presents this peculiarity, that 

 the centre of its irregularly rounded figure does not coincide 

 exactly with the pole, but is situated at another point, which is 

 nearly always the same, and is distant from the pole about 300 

 kilometres (180 miles) in the direction of the Mare Erythrxum. 

 From this we conclude that when the area of the snow is 

 reduced to its smallest extent, that the south pole of Mars is 

 uncovered ; and therefore, perhaps, the problem of reaching it 

 upon this planet is easier than upon the Earth. The southern 

 snow is in the midst of a huge dark spot, which with its 

 branches occupies nearly one-third of the whole surface of 

 Mars, and is supposed to represent its principal ocean. Hence 

 the analogy with our arctic and antarctic snows may be said to 

 be complete, and especially so with the antarctic one. 



The mass of the northern snow-cap of Mars is on the other 

 hand centred almost exactly upon its pole. It is located in a 

 region of yellow colour, which we are accustomed to consider 

 as representing the continent of the planet. From this arises a 

 singular phenomenon which has no analogy upon the Earth. 

 At the melting of the snows, accumulated at that pole during 

 the long night of ten months and more, the liquid mass produced 

 in that operation is diffused around the circumference of the 

 snowy region, converting a large zone of surrounding land into 

 a temporary sea, and filling all the lower regions. This pro- 

 duces a gigantic inundation, which has led some observers to 

 suppose the existence of another ocean in those parts, but which 

 does not really exist in that place, at least as a permanent sea. 

 We see then (the last opportunity was in 18S4) the white spot 

 of the snow surrounded by a dark zone, which follows its peri- 

 meter in its progressive diminution, upon a constantly diminish- 

 ing circumference. The outer part of this zone branches 

 out into dark lines, which occupy all the surrounding region, 

 and seem to be distributory canals, by which the liquid mass 

 may return to its natural position. This produces in these 

 regions very extensive lakes, such as that designated upon the 

 map by the name of Lacus Hyferhorcus ; the neighbouring 

 interior sea called Mare Acidalium becomes more black, and 

 more conspicuous. And it is to be remembered as a very pro- 

 bable thing, that the flowing of this melted snow is the cause 

 which determines principally the hydrographic state of the 

 planet, and the variations that are periodically observed in its 

 aspect. Something similar would be seen upon the Earth, if 

 one of our poles came to be located suddenly in the centre of 

 .\sia or of Africa. As things stand at present, we may find a 

 miniature image of these conditions in the flooding that is 

 observed in our streams at the melting of the Alpine snows. 



Other white spots of a transitory character, and of a less 

 regular arrangement, are formed in the southern hemisphere, 

 upon the islands near the pole, and also in the opposite hemi- 

 sphere, whitish regions appear at times surrounding the north 

 pole, and reaching to 50" and 55^ of latitude. They are per- 

 haps transitory snows, similar to those which are observed in 

 our latitudes. But also in the torrid zone of Mars are seen 

 some very small white spots more or le>s persistent. Perhaps 

 we may be permitted to account for these by the existence of 

 a mountain capalile of supporting extensive ice-fields. The 

 existence of such a mountain has been supposed also by some 

 recent observers, founded upon other facts. 



Martian Mf.teoroi.ogv. 

 As has been slated, the polar snows of Mars prove, in an in- 

 controvertible manner, that this planet, like the Earth, is sur- 

 rounded by an atmosphere capable of transporting vapour from 

 one place to another. These snows are in fact precipitations of 



1 A note on the melting of the southern snow-cap this year appeared 

 the last number of Natuke (p. 64). 



