rientifk Jteuts 



FOR GENERAL READERS. 



Vol. II. 



NOVEMBER 23, 1888. 



No. 



Scientific Table Talk 



New Heating Appliances (Illus.) 

 The Greenland Expedition 



The Neglected Sense (Illus.) 



Artificial Caverns 

 General Notes ... 



On Vernation and the Methods of De- 

 velopment of Foliage, as Protective 



against Radiation (Illus.) 



The Urania Riphoeus ... 

 Natural History — 



Mimetism in Animals (Illus.) 



The Tsetse 



The Horses of the Pampas ... 



Miscellaneous Notes 



PAGE 

 521 



523 

 523 

 525 

 526 



527 



529 

 53° 



531 



532 



533 

 533 



CONTENTS. 



The Teeth of Whales 533 



The Pineal or Parietal Eye 534 



Fluorescence and Phosphorescence ... 535 

 Reviews — 



An Introduction to Practical Inor- 

 ganic Chemistry ... ... ... 535 



Handbook to Breeding, Diseases, 

 Treatment, Care, and Choice of 

 Foreign Aviary Birds, including 

 how to Tame and Teach Birds to 

 Speak, and Chapters on Manage- 

 ment, Cages, Seeds, Insect Foods, 



Pastes, Dainties, etc 535 



Abstracts of Papers, Lectures, etc. — 



Royal Society 536 





PAGE 



Institution of Civil Engineers 



- 537 



Geological Society ... 



... 538 



Physical Society 



... 540 



Entomological Society 



... 540 



Liverpool Geological Society 



... 541 



Royal Horticultural Society... 



... 541 



Miscellaneous Societies 



... 542 



Recent Inventions ... 



- 543 



Announcements 



... 544 



Sales and Exchanges ... 



... 544 



Selected Books ... 



... 544 



Diary for Next Week 



... 544 



Notices 



... 544 



Meteorological Returns 



... 544 



SCIENTIFIC TABLE TALK. 



By W. Mattieu Williams, F.R.A.S., F.C.S. 



The readers of Scientific News have had before them, in 

 Nos. 17, 18, ig, a description of the curious observations 

 that have been rec ntly made on " the mysteries of 

 Mars," and of some of the efforts to explain them. 



Twenty years ago I wrote an essay on " The Meteor- 

 ology of Mars " which constitutes the sixteenth chapter 

 of " The Fuel of the Sun," and have quietly watched the 

 observations that have been made at each subsequent 

 opposition. These observations not only confirm my 

 original views of the atmospheric conditions prevailing 

 on this planet, but as regards the " canals " they pre- 

 sent phenomena which I partially anticipated, and which 

 follow as natural consequences of the conditions I then 

 theoretically described. 



The reader may ask, What has the meteorology of 

 Mars to do with the fuel of the sun ? A short explana- 

 tion will answer this. In the first chapters of the book 

 I discuss the limits of our atmosphere, and show reasons 

 for concluding that it and our aqueous envelope are 

 merely portions of the universal medium pervading all 

 space, and that their quantity attached to each orb is pro- 

 portionate to its gravitating energy. This was a heresy 

 twenty years ago, but is now widely accepted. 



Knowing the gravitating energy of the earth and the 

 quantity of its atmosphere, we are supplied with units 

 affording data for calculating the density of the atmo- 

 sphere of other orbs,provided we know respectively these 

 two elements and their dimensions. Solar phenomena 

 follow of necessity in all cases where there are solar 

 dimensions. 



As an experimentum cruris I calculated thus the theo- 

 retical atmospheres of the moon and all our planets, and 

 compared the results with observed phenomena. All 

 came right excepting Mars, which had hitherto been de- 

 scribed as a planet with a dense atmosphere, while my 

 calculation gave it a total supply of atmospheric matter 

 equal to about j s of our own, or, allowing for the smaller 

 base upon which it is resting, it becomes an atmosphere 

 having a pressure of 2| lbs. on each square inch of the 



planet's surface, against 15 lbs. on ours. Therefore, 

 the mercurial barometer should there stand at a mean 

 of s| inches, and water should boil at 138 degs. Fah., 

 be as volatile as bromine, and much more so than alcohol 

 down here. 



But what were the grounds upon which the accepted 

 estimate of the planet's dense atmosphere was based ? 

 I found on examination that there were none beyond a 

 fanciful assumed provision for maintaining a tempera- 

 ture suitable for supposed human inhabitants. No 

 measure of refraction by occultation had been made, and 

 when fairly interpreted, all the telescopic phenomena 

 flatly contradicted it. 



If such an atmosphere prevailed with the assumed 

 protecting vapours, Mars should have dense clouds. Mars 

 has no such dense clouds. But there is something that 

 occasionally obscures the planet, especially towards its 

 outer visible boundaries, during opposition, when we best 

 see it. 



With such an atmosphere as my calculation demands, 

 with such volatile water, on a planet with the intensity of 

 solar heat at its surface less than half of that on the earth 

 (o'43i to unity), there could exist "nothing denser than a 

 thin veil of stratus, or cirro-stratus, cloud, formed of ice 

 crystals, the kind of cloud or mist which in our upper at- 

 mosphere makes halosround the moon. The mid-day region 

 and a certain distance around it would but rarely be subject 

 to this small degree of obscuration, as the sun's heat there 

 should, under ordinary circumstances, hold in transparent 

 solution all the vapours it had raised." Outside of this 

 circle, north, south, east, and west, " a deposition of hoar 

 frost must be continually taking place all round the disc 

 of the planet, and this will commence at a certain angular 

 distance from the meridian centre of the disc, and increase 

 gradually towards the circumference. The rotation of 

 the planet will, however, produce a considerable differ- 

 ence in the results of this deposition. All that falls on 

 the east and west sides 01 the planet will be thawed and 

 evaporated by the next day's sunshine, so that the maxi- 

 mum accumulation in these directions can be but one 

 night's deposition ; but on the north and south there will 

 be a continuous accumulation which will only be thawed 



