Jlrienttfk JUujb 



FOR GENERAL READERS. 



Vol. II. 



OCTOBER s, 1888. 



No. 1 



*t 



CONTENTS. 



PAGE 



Scientific Table Talk 353 



The Volcanic Eruption in- Japan. " 



[Illus.) 3 54 



The Ancient Inhabitants of the Canary 



Islands. (Illus.) 35 5 



General Notes 359 



Some Photo-micrographic Apparatus 



(Illus.) 36' 



Natural History — 

 The Crustacea of the Sea Bottom... 363 

 A Gigantic Spider 364 



Sparrow Hawk and Water Hens ... 



Walking Home 



Do Snakes Fascinate their Victims ? 



Miscellaneous Notes 



Water Eggs of Insects .. 

 The Distribution of Colours in Animals 

 Electrical Transmission of Power 

 Abstracts of Papers, Lectures, etc. — 



Society of Engineers... 



Manchester Microscopical Society... 



Miscellaneous Societies 



PAGE 

 364 

 3 6 4 

 364 

 364 

 365 

 365 

 366 



370 

 37' 

 372 



Recent Inventions 



Correspondence — 



A Safe Insecticide — Strange Action of 

 a Beetle— Satellites of Mars — Food 

 of the Leech — The S parrow ... 



Technical Education Notes 



Sales and Exchanges 



Selected Books ... ... ... ... 



Notices 



Meteorological Returns 



PAGE 



373 



374 

 375 

 376 

 376 

 376 

 376 



SCIENTIFIC TABLE TALK. 



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



In my last I discussed the series of changes which occur 

 when a thin, filmy substance, such as a leaf or a dead 

 butterfly falls upon a glacier of moderate slope, culmina- 

 ting in the complete perforation of the glacier down to its 

 base by a trou de cascade. 



The reader may have noted that I carefully specified a 

 supply of clear water in the rill flowing into the baig- 

 noire. But the water of these glacier rills is not always 

 clear, not usually clear,especially if it flows down the slope 

 of the moraine ridge. ■ On the Unteraar glacier, with its 

 great medial backbone ridge of ice, rising as much as eighty 

 feet above the general level, and coated with rock debris, 

 all the rills that flow from this source carry with them 

 more or less of the sand that results from the continuous 

 disintegration of the rock fragments subjected to a 

 succession of freezing nights and scorching days, such 

 succession being one of the peculiarities of glacier 

 climate to which many glacial phenomena are due. 



One of these rills flowing during the summer day- 

 time down the moraine slope into a baignoire and carrying 

 with it the particles of rock deposits them at the bottom 

 of the basin, where they accumulate. The effect of such 

 a covering of the concavity is easily understood. It must 

 put a stop to all further excavation of that portion of the 

 basin which is so protected. The warmer sinking water 

 can no longer continue scooping the bottom, though it 

 may act on the sides. But the general surface of the 

 glacier all around the basin is lowering daily. Suppos- 

 ing the baignoire to be five feet deep when this protection 

 »f the bottom begins to be efficient, and that the summer 

 ablation proceeds at an average rate of two inches daily, 

 what will happen at the end of thirty days ? 



It is evident that the deposit of sand or gravel will now 

 become level with the surface of the surrounding ice, and 

 its quantity will be considerable, as the deposition was 

 continued during the thirty days. We shall thus have a 

 pocket of sand of respectable depth imbedded in the 

 glacier. But the sun goes on thawing the general sur- 

 face, while that forming the bottom and sides of the sand 

 pocket is protected. Thus the pocket or basin full of 

 sand will presently be raised with its rim above the 

 general level ; it will stand upon a pedestal ring of ice. 



The sun, however, will not spare this pedestal, will 

 thaw its sides and thus undermine the edges of the 

 basin. This undermining will cause some of the sand 

 to trickle over. This will coat the sloping sides of the 

 pedestal and thus protect it. 



It is evident that the supply of such protection to the 

 sloping slides will slightly diminish the diameter of the 

 basin itself; its own edge will become somewhat thawed 

 all round. This action will be repeated daily, and as the 

 surrounding surface of the ice continually thaws down 

 lower and lower, the outspread of the protected base 

 increases, and the summit basin diminishes in diameter 

 by the thawing of its edges, until at last it contracts to a 

 mere point, and thus a cone is formed which, as Agassiz 

 says, appears so like a loose heap of rubbish that at first 

 acquaintance one can scarcely resist the temptation to 

 overthrow it with the foot or a stick, but in attempting 

 to do so no little astonishment is excited by its firmness, 

 which is explained on brushing off the surface sand, 

 when a cone of clear ice, continuous with the bulk of the 

 glacier, is revealed. 



Schuttkegel (rubbish cones) is the name they have re- 

 ceived from the mountaineers, and this is adopted by 

 Agassiz, who refers to the fact that they were in 1840 

 practically unknown to science, though so interesting in 

 their growth, and supplying, like the glacier tables, such 

 clear demonstration of the surface thawing down of 

 glaciers. They abound on the Zermatt and Unteraar 

 glaciers, but are rare on other glaciers for the reasons 

 already stated in reference to glacier tables. 



They are not ordinary cones of circular (horizontal) 

 section, but are all elliptical, the longer axis of the ellipse 

 lying in the meridian of the place, and the southern slope 

 of the cone steeper than the northern. The reasons for 

 this I have already explained in connection with the 

 glacier tables, meridian holes, and baignoires. Those 

 that I saw varied from about one to three feet in height. 

 Agassiz has found them ranging from a few inches in 

 height to six and ten feet across at the base, and four to 

 five feet high. 



These are the monuments of the dead butterflies to 

 which I first referred. Some readers may imagine that 

 the idea of butterfly origin is rather fanciful, but such is 

 not the case. A thin film is demanded — a leaf will do — 

 but trees do not grow on glaciers, and the leaves that are 



