(•) 



NATUKAL SCIENCE NEWS. 



Stephen Bishop; his remains now 

 rest in the tangled grave-yard near 

 the garden. 



Mammoth Cave has a noble ves- 

 tibule! Amid tulip-trees and 

 grape-vines, maples and butter- 

 nuts, fringing ferns and green 

 mosses, is the entrance to this un- 

 der-ground palace. From a frown- 

 ing ledge a cascade leaps to the 

 rocks below, where it vanishes at 

 once, forming no running stream. 

 The entrance to the cave is one 

 hundred and ninety-four feet above 

 water-level, and one hundred and 

 eighteen feet below the summit of 

 the bluff on which stands the 

 hotel. A winding flight of seventy 

 stone steps conducts us around the 

 cascade into an ante-chamber. At 

 the end of this is a grated iron 

 door to which each guide has a % 

 key. As we cross the portal, a 

 strong current of air blows out our 

 lights; but a few yards within, 

 where the draft is weaker, we re- 

 kindle them. This phenomenon 

 is due to a marked difference in 

 temperature between the atmos- 

 phere within and that without the 

 Cave. Both the air and the water 

 in the cave nearly correspond with 

 the heat of the earth itself, which 

 in that latitude varies but little 

 from fifty-six degrees Fahrenheit 

 throughout the year. In some of 

 of the dryer chambers the mercury 

 rises to fifty-eight degrees, and in 

 some of the springs and pools it 

 falls to fifty-two degrees. The 

 thermometer at the hotel-office in- 

 dicated eighty degrees in the 

 shade, a difference on that day of 

 nearly thirty degrees, which caus- 

 ed, of course, a strong outward 

 flow. 



The simple truth about Mam- 

 moth Cave surpasses the most in- 

 genously woven fabrication. Its 

 areal diameter is nine or ten miles. 

 Its known and numbered avenues 

 are two hundred and twenty-three, 

 and their united length equals one 

 hundred and fifty to two hundred 

 miles. Twelve million cubic 

 yards of space have been excavated 

 from the rocks by the agency of air 

 and water. Such are the windings, 

 crossings, and evolutions of this 

 labyrinth, that we found, by the time 

 our explorations were ended, on 

 adding up all our daily trips in and 

 out, we had traveled about one 

 hundred miles under ground. 



The main Cave, so called in dis- 

 tinction from minor avenues open- 

 ing into it, extends like a deserted 

 river-bed, through a succession of 

 noble arches and domes, to a point 

 six miles within, where it is abrupt- 

 ly closed by fallen rocks. 



Singular effects are produced by 

 the incrustations of gypsum stain- 

 ed by the black oxide of iron, seem- 

 ing to cut gigantic silhouettes from 

 the ceiling of white limestone. At 

 first we ridiculed these fancies, but 

 at last they fascinated us. Bears, 

 monkeys, anteaters, catamounts, 

 indeed, a whole menagerie is on 

 exhibition, including the old mam- 

 moth himself. We were especially 

 interested in a side-show of a giant 

 and giantess playfully tossing pa- 

 pooses to and fro. The Giant's 

 Coffin is near by — a rock shaped 

 like a mighty sarcophagus. It is 

 detached from the ceiling, walls, 

 and floor, resting its weight on 

 stone trestles, and equals in size 

 one of the famous blocks of Baal- 

 bek, being forty feet long, twenty 

 wide, and eight deep. 



A strangely beautiful transforma- 

 tion scene is exhibited in the Star 

 Chamber, a hall seventy feet wide, 

 sixty high, and five hundred long. 

 The lofty ceiling is coated with 

 black gypsum, studded with thous- 

 ands of white spots, caused by the 

 efflorescence of sulphate of magne- 

 sia. Our guide asks us to sit down 

 on a log bench by the wall, and 

 then, collecting the lamps, vanishes 

 behind a jutting rock, whence, by 

 adroit manipulations, he throws 

 shadows flitting like clouds ath- 

 wart the starry vault. The effect 

 is extremely fine, and the illusion 

 is complete. One can easily per- 

 suade himself that the roof is re- 

 moved, and that he looks up from 

 a deep valley into the real heavens. 



"Good-night" says the guide; 

 •'I will see you again in the morn- 

 ing." 



With this leave-taking he plunges 

 into a gorge, and we are in utter 

 darkness. Even the blackest mid- 

 night in the upper world has from 

 some quarter a few scattered rays; 

 but here the gloom is without a 

 gleam. In the absolute silence 

 that ensues, we hear the beating 

 of our hearts. The painful sus- 

 pense is at length broken by one of 

 those strange outbursts of laughter 

 that come when least expected; 

 and, then we indignantly ask each 

 other the meaning of this sudden 

 desertion. But while we are round- 

 ly berating the guide's treachery, 

 we see in the remote distance a 

 faint glimmer, like the first streak 

 of dawn. The light increases 

 in volume till it tinges the tips 

 of the rocks, like tops of hills 

 far away. The horizon is bathed 

 in rosy hues, and we are prepared 

 to see the sun rise, when all at 

 once the guide appears, swinging 

 his cluster of lamps, and asking 



us how we like the performance. 

 Loudly encored, he repeats the 

 transformations again and again — j 

 starlight, moonlight, thunder;, 

 clouds, midnight, and day-dawn, 

 heralded by cock-crowing, the bark- 

 ing of dogs, lowing of cattle, and 

 various other farm-yard sounds; 

 until, weary of an entertainment 

 that long ago lost its novelty for 

 him, he bids us resume our line of 

 march. It is doubtful if one visi- 

 tor in fifty goes farther into the 

 main cave than the Star Chamber; 

 but none fail to see this favorite 

 hall of illusions. 'We revisited it 

 frequently during our stay. The 

 path to it is dry and well trod- 

 den. A pleasing incident comes 

 to mind, showing how easily it 

 may be reached, although more 

 than a mile under-ground. One 

 evening after tea I had entered 

 thus far alone, without a guide, 

 and after studying for a while the 

 peculiar effects of light and shade, 

 I sat down on the log bench and 

 put my lamps out, in order to en- 

 joy the luxury of utter darkness, 

 silence and solitude. But ere long 

 voices were heard and mysterious 

 peals of laughter. Soon the day- 

 dawn effect was unexpectedly pro- 

 duced, by the approach of a party 

 of jocund youths and maidens, 

 with lights, who, having dressed 

 for a hop, first paid a visit to this 

 enchanted ground, and as cave- 

 dust never flies nor sticks, they did 

 so without a speck on polished 

 boots or trailing robes. 



The avenues, as all side-passages 

 are termed, vary in importance, 

 some of them rivaling the main 

 Cave, while others involve grievous 

 climbing and crawling, with small 

 recompense. 



(to be continued.) 



The Coral Islands. 



In asking his hearers to accom- 

 pany him on a sailing expedition, 

 notwithstanding the stormy weath- 

 er outside, the lecturer assured 

 them that they would be most like- 

 ly to encounter a calm sea and fair 

 weather on the magnificent >waters 

 of the Pacific ocean, with its 

 thousands of islands far away from 

 any coast. Those who are famil- 

 iar with the glowing narrations of 

 Captain Cook and other navigators 

 will remember that the presence of 

 an island is recognized, long before 

 it becomes visible, by clouds direct- 

 ly above it in the otherwise clear ( 

 sky. The land absorbs the heat of j 

 the sun and accumulates it faster 

 than the water; soon an ascending 



