76 



SCIENCE. 



[Vol. XXI. No. 525 



SCIENCE; 



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RECENT OBSERV.VTIONS AT KILAUEA. • 



BY JOSIAH keep, MILLS COLLEGE, ALAMEDA CO., CAL. 



The great volcano of Kilauea, on the island of Hawaii, like all 

 other live things, is constantly changing, and any report of its 

 condition is liable to need important corrections on the advent of 

 the next steamer. The last great explosion, however, took place 

 in 1790, more than a century ago, and since that time the huge 

 pit has been fillinp; up with black lava and the area of activity 

 has been narrowing. During the month of July last I had an 

 opportunity to observe the igneous action under exceptionally 

 favorable circumstances, and a record of its condition at that 

 time can hardly fail to be valuable for comparison with past and 

 future reports. 



The crater is a huge depression or pit, about three miles long 

 and two miles broad. The walls are mostly precipitous, though 

 quite irregular, and the floor is some three hundred feet below 

 the surface of the island at that point. Forty years ago it was 

 several hundred feet lower. Standing on the brink of the crater 

 and looking down, one is reminded of a great cellar after a fire. 

 Every thing is black or rusty, and the smoke and steam coming 

 up from dark clefts put you in mind of the charred and smoking 

 timbers to be seen after a conflagration. A zigzag path, a mile 

 long, leads down through ferns and bushes to the black lava, and 

 then you step out on a sea of absolute desolation. The lava is 

 cold now, but there are the most abundant evidences of its recent 

 fusion. The surface is gieatly varied; here being nearly smooth, 

 and there swelling up into steep hillocks, perhaps with caves be- 

 neath them, into which you can creep or perhaps walk upright. 

 Cracks abound, and out of some of them the hot slag has oozed, 

 and flowed, and cooled, and hardened. 



After walking over two miles of this rough floor I came sud- 

 denly to the brink of a second pit in the floor of the greater one. 

 This second pit, the " Halem' oum' ou" of the natives, is about 

 half a mile in diameter, and at the time of my visit its floor was 

 some two hundred and fifty feet below the point where I was 

 standing. Some adventurous climbers descended the precipitous 

 sides and actually stood on the freshly-cooled lava, but I did not 

 accompany them. In the centre of this lower floor was the lake 

 of moulten lava, nearly circular in outline, and about one thou- 

 sand feet across. Its level surface was largely covered by a thin, 

 gray crust, portions of which would often sink and reveal the 

 glowing liquid beneath. 



The fiery lake was never free from agitations, particularly 

 around its edges, but the extent and violence of the activity were 

 constantly changing. Occasionally a liquid hillock would rise 

 like an enormous bubble, then sink back again, while a puff of 

 thin, blue smoke would slowly rise and float off from the spot, 

 showing that in a condensed state it had doubtless been the lifting 

 agent. But most of the agitation resembled the lively boiling of 

 a kettle of water over a brisk fire. The glowing fountains would 

 jump and dance in the wildest manner, often throwing up the 



fiery drops to a height of fifty feet, while waves of lava would 

 surge against the curb of the lake with a sound like that of ocean 

 breakers In the night time, seen through an opera glass, the 

 display was beautiful and grand beyond description. 



The continual falling of half-cooled drops of lava around the 

 edge of the lake, combined with the wash of the fire-waves, serves 

 to build up a curb, which grows in proportion to the activity of 

 the lake. On one side of the pool of melted rock its top was some 

 thirty feet higher than the floor which joined the base of the curb 

 to the walls of the pit. One night the lava rose in the lake and 

 poured over the curb on that side in a magnificent cascade of fire. 

 It was not possible to get in front of the overflow, but it was 

 estimated that the stream was fifty feet wide. The motion of 

 the current was like that of a water cascade, but when the flood 

 reached the floor of the pit it quickly began to congeal on the 

 lop. while the under part ran on till it reached the confining 

 walls. Another overflow, where the curb was not so high, came 

 directly towards my point of observation, and I could clearly see 

 that the central point of the stream moved swiftest, causing the 

 hardening waves to assume the well-known crescent forms. 



By such overflows from the moulten lake the inner pit is being 

 gradually filled up; in fact, its floor has risen several hundred 

 feet the past few years. The lake rises pari passu, the curb never 

 rising very high above the floor. What the result will be is un- 

 certain. Should the lava continue to rise, the pit will soon be 

 filled and will overflow into the basin of Kilauea itself. But in- 

 stead of this the bottom of the pit may drop out, so to speak, as 

 it did very suddenly before this last rise, and instead of gazing 

 into a lake of fire the tourist may be compelled to look into a 

 huge smoking hole, some five or six hundred feet deep. Doubtless 

 the whole floor of Kilauea rests on a very hot foundation, as the 

 steam which ascends from many cracks indicates, but at the time 

 of my visit there was no melted lava visible except in the lake 

 which I have described. 



The questions presented by these phenomena are intensely in- 

 teresting; but the more I observed the boiling of the lava, the 

 more I became convinced that aqueous vapor is not the chief 

 agent which does the work, though it may be concerned in start- 

 ing the tremendous chemical action, perhaps a decomposition of 

 sulphides, which I think is the source both of the heat and of 

 the commotion. 



EXTREMES IN THE PLANT WORLD. 



BY PROF. J. I. D. HCNDS, LEBANON, TENN 



Or living organisms, the largest, as well as the smallest, are found' 

 in the vegetable kingdom. In point of bulk, even the elephant 

 compares unfavorably with the largest trees, and the smallest 

 living objects, seen by the help of the microscope, are undoubtedly 

 plants. 



The largest plants known are what are popularly called •' the 

 big trees of California." They are conifers, belonging to the 

 genus Sequoia, which is intermediate between the firs and 

 cypresses. There are two species, S. sempervirens and S. gigantea. 

 The former is the common redwood and abounds on the Coaet 

 Range from the southern part of California northward into 

 Oregon. The latter is not so common, but grows to a larger 

 size. " It is confined to the western portion of the great Cali- 

 fornia range, occurring chiefly in detached groups, locally called 

 ' groves,' at an altitude of from 4,000 to 5,000 feet above the 

 sea." It grows to enormous size, varying in height from 200 to 

 nearly 400 feet and in diameter from 20 to 30 feet. One tree in 

 Calaveras County is 325 feet high and 45 feet in circumference 

 six feet from the ground. Another measured 90 feetin girth and 

 331 in height. Some of these trees are supposed to be 3,000 years 

 old. They were then in their vigor when the Roman Empire was 

 at the height of its glory and hoary with age when Columbus 

 landed on the American shore. 



Let us now turn from these giants of the forest to those plants 

 which can only be seen with the higher powers of the microscope. 

 The smallest of these and at the same time the smallest of living 

 things are the plants known as Bacteria. They have an average 

 diameter of one twenty-five thousandth of an inch and a length 



