328 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Januakv, 1906. 



pressure becomes great enough to prevent further 

 liquefaction, in which case a section through the earth 

 would show three concentric rings, the innermost 

 having a diameter of over 7,000 miles and marking 

 the extremities of the solid nucleus, then a ring, about 

 7,Soo miles in diameter, defining the limits of the liquid 

 substratum, and finally there would be the earth's crust, 

 which, \arving as it would according to the position of 

 mountain, land, and water, probably in no place ex- 

 ceeds a depth of over 70 miles. 



A very potent argument has been urged against this 

 second assumption to the effect that, if the crust were 

 so thin as the theory states, it would yield to the de- 

 forming influence of the sun and the moon; in which 

 case the water would be drawn up with the earth, and 

 thus no sensible tidal effects could be produced. In 

 order to counteract this attraction it would be necessary 

 to admit that the thickness of the earth's crust is at 

 least 2,000 miles. 



An unsatisfactory compromise has thus been sug- 

 gested, by which it is supposed that tlie earth is at the 

 present time solid throughout (having passed through 

 the stage of alternate solidity and fluidity), but that 

 large fluid cavities exist throughout the mass. 



If the reader should find himself incapable of coming 

 to any definite conclusion on this question, how much 

 more impossible is it for the student of geology (or 

 mathematics) to settle the difficulty satisfactorily ? 

 Each theory initially commends itself with much 

 plausibility to its reader, but as the more important but 

 less apparent tests are applied, certain defects come 

 into prominence. 



Fisher's Theory. 



Fisher succeeded in forming a theory that would 

 comprehend and explain all the difficulties that each 

 pre\ ious assumption had encountered. 



He accepted the idea of the existence of a liquid 

 substratum, with this difference, that it consisted of a 

 mixture of fused rock and a dissolved gas (in all 

 probability hydrogen). 



The origin of earthquakes and volcanoes can be satis- 

 factorily explained on this assumption, which has the 

 additional qualification of accounting for the appear- 

 ance of vast quantities of that gas [i.e., hydrogen) in 

 all volcanic outbursts. Furthermore, the fused mass, 

 which Fisher supposes to exist, would not give rise to 

 any tides within the earth's crust, and thus one of the 

 most serious objections to the " liquid substratum 

 hypothesis " (which is itself based on the fundamental 

 notions of the effect of heat on solids) is satisfac- 

 torily removed. At the same time the theory admits 

 the possibility that the fused mass tnay communicate 

 its movements to the earth's surface (although not in 

 the form of " tides "), which deduction, taken with all 

 the other scientific explanations, should strongly recom- 

 mend the theory to all whom it may interest. 



Australian Meteorology 



Up to the present day, each of the \ arious institutions 

 for studying weather in .Australia has been 

 working independently for its own local and par- 

 ticular needs, and there has been no centr;U bureau 

 whose business it has been to gather and discuss this 



wealth O'f priceless material, now rapidly accumulating, 

 to advance the knowledge of the meteorolwjy of this 

 portion of the globe as a \\hole. It is true that vali;mt 

 attempts ha\e been made by indixiduals to tackle this 

 inquiry, and, thanks to their efforts, much valuable in- 

 formation has been gleaned. 



Australia, as e\eryone knows, is a verv large tract 

 of country, extending considerably in both latitude and 

 longitude. There is undoubtedly a very close connec- 

 tion between Indian and .Australian weather, so that a 

 rigorous study of the latter would, in all probability, 

 be extremely useful in helping to unravel the vagaries 

 of the former. 



Disastrous droughts are not infrequent in .Australia, 

 and at these epochs, when the natural water supply of 

 the country is cut off, millions of sheep die, and in 

 consequence the assets of the country are considerably 

 diminished. 



It is therefore of the highest importance for the 

 future welfare of the Australian Continent that, in 

 addition tO' the various institutions which are at present 

 collecting and publishing meteorological observations, 

 there should be added a central bureau to take a 

 broader view of the situation and co-ordinate and dis- 

 cuss not only the Australian meteorological data in 

 ioio, but those gleaned from neighbouring islands and 

 seas. 



According to recent information there seems a 

 prospect of such a scheme being brought into being, 

 and if it be carried out in a practical manner, the 

 country will undoiubtedly be benefited in the course of 

 time. Droughts, of course, cannot be stopped, but 

 their effects may be mitigated by an intelligent use of 

 the knowledge that will be gained by such an institu- 

 tion, after a careful study of the weather changes, 

 changes which have every appearance of being- of a 

 periodic nature. 



A Successful Flying 

 Machine. 



It is nearly two years (February, 1904) since we announced 

 the successful ascent by Messrs. Wilbur and Orville Wright in 

 an aeroplane of their construction in North Carolina. It 

 seemed at the time as if the accounts might have been 

 exaggerated, and as no further news was heard of these 

 inventors until a few days ago. it was natural to suppose that 

 the apparatus was not quite so perfect as the sanguine makers 

 had at first hoped. Now, however, in a letter which was read 

 at a meeting of the Aeronautical Society on December 15, they 

 make the startling announcement that they have been steadily 

 continuing their experiments, and have been rewarded with 

 highly satisfactory results. No details of the machine itself 

 are given, for the inventors do not wish such to be published 

 at the present stage, but it is presumed to be a motor- 

 propelled aeroplane, entirely dependent for its lifting power 

 on the screw propellers. They state that during September 

 and October last flights were made on eight different days, 

 and that the distances covered during these flights varied from 

 Ti to 245 miles. The speed was about 3S miles an hour, and 

 on each occasion the machine returned to its point of depar- 

 ture without suffering the slightest damage. The longest 

 flight lasted no less than 3S min. 3 sees. Such an account 

 may well be received by the general public with some in- 

 credulity, but we know the inventors to be thoroughly sound 

 and unassuming men who would not be likely to make such 

 an announcement without very good grounds. 



