346 



SCIENCE. 



[Vol. XXI. No. 542 



result. The illusion is quite complete; I seem to be looking at an 

 actual pattern. The use of a material point of regard, as the tip 

 of the finger, was not, as Piofessor LeConte seems to have un- 

 derstood me, to aid in properly fixing the axes of the eyes, but 

 simply to make sure on which side of the actual pattern the 

 horopter lay — the all-important fact in the experiment. I may 

 add, that in my case the coalescence of the images is easier with 

 a more distant than with a nearer point of regard — contrary to 

 Professor LeConte's experience. It seems to me that it would 

 be valuable to secure some additional evidence as to the way in 

 which the phenomenon strikes a person who has had no previ- 

 ous knowledge of its existence, say by using a stereoscope with- 

 out lenses, fixing the distance of a point in monocular vision and 

 then suddenly introducing a pattern, the observer being simply 

 asked to estimate its distance. In closing, let me say that I lay 

 no stress on my remarks in explanation of my own case. It 

 really is more or less of a mystery, but it surely need not remain 

 so. The abnormal eyes of Dal con did great things for the 

 theory of color vision, and indeed it is from the abnormal more 

 than from the normal cases that fruitful trains of thought are apt 

 to take their rise. I esteem myself fortunate to have interested 

 Profes.sor LeConte, and I hope that this is by no means the last 

 thought that he will give to the matter. 



Arthur E. Bostavick. 



MoBtclalr, N.J., June 19. 



A Night-Singing Cat-Bird. 



Perhaps it is not a rare occurrence, but I never heard of such a 

 thing before, and I give the incident for what it is worth. A few 

 evenings since I heard a cat-bird sing for nearly an hour just be- 

 fore midnight. The weather was mild, with not enough moon- 

 light to cast a shadow. The bird's song was somewhat intermit- 

 tent and scarcely so rapturous as his usual sunset or sunrise 

 singing. In the intervals there occasionally came one or two of 

 the mewing utterances characteristic of the bird. 



A. Stevenson. 



Arthur, Onlario. 



Is it a Paleolith? 



A STONE axe has just been found in a field about eight miles 

 northeast of this place, which very nearly proves (if not quite so) 

 that man existed during, or prior to, the glacial period in North 

 America. It was found by A. A. Newlin, on the summit-level 

 in this (Parke) county, Indiana, on the south side of Sugar Creek. 

 It is 6^ inches long, 2f inches wide on the blade, 4:j\ inches wide 

 at the groove (or eye of our steel axes). 3* inches wide at the 

 "back," or " poll," and is 1^ inches thick, and, I am confident, 

 was, when first made, nearly two inches thick. 



One side is ground flat, and by glacial action, without any 

 doubt. By that grind the groove was planed almost out on that 

 side, and has been re-cut or filed out by some Indian long ages 

 after the Indian who first fashioned the axe. The striations run 

 from edge to poll, and the axe was moving edge forward, as the 

 striations indicate, for they are deeper cut toward the edge, and 

 weaker, become shallower and less distinct, toward the poll. 



The opposite, or convex, side of the axe has been striated just 

 enough to produce a distinct plane, which inclines to (or from) 

 the flat side about eleven degrees. 



The poll, the ends (as timber men call that part of the axe near- 

 est to and farthest from the hand when using), the present con- 

 vex side, and the grooves around the ends show the deepest and 

 oldest weather-pits. Then the glaciated, flat side shows the next 

 oldest weathering. Next, the newly-deepened groove on the flat 

 side, and, also, a little deepening of the groove on the convex 

 side, where the grinding had made tlie groove somewhat shallow, 

 show the next oldest weathering; and, last, the smooth, whetted 

 edge shows very little weather wear. 



This axe was found about one hundred miles, north of the 

 southern boundary of the glacial drift on the Waisash River. I 

 have found eleven places in the county where the rock, in place, 

 is strongly and clearly glaciated, and three places have been found 

 by other parties. The erratic bowlders which are striated on one 



to flve sides are countless (to say nothing of those not marked), 

 and I have examined them and studied them a great deal, and 

 think I am not a bad judge of their comparative exposures and de- 

 compositions. As a result of my experience and judgment, I am 

 strongly inclined to believe that this axe was made before, or 

 during the glacier. That it was lost, or in some way fell into the 

 sweep of the glacier and was ground flat on one side and striated 

 a little on the other. That, after the glacier had receded, it was 

 found, repaired, sharpened, and used till the steel tomahawk took 

 its place, when it was cast aside. I feel confirient that experienced 

 archfeologists will so decide. Jno. T. Campbell. 



Rockville, Indiana. 



Cloud Formation. 



I wish to call the attention of meteorologists to a rather peculiar 

 phenomenon witnessed by me several times last winter. 



The slough between King's River and the San Joaquin, overflows 

 in seasons of high water, causing dense growths of tule (Scirpus 

 lacustris, or round tule, and Typha latifolia, or flat tule), often 

 ten feet high. The buccaroes of the large stock ranches burn the 

 dead matter in winter, to clear the land that the stock may get 

 the young feed. 



On Jan. 28, at 3.30 p. m., I noticed one of these fires. The 

 wind was northwest, slight, and quite warm; the weather had 

 been showery for a few days previous, but, saving a few clouds of 

 the cirrus type, the sky was clear. The fire was not extensive, 

 but made a dense smoke which rose in a nearly perpendicular 

 column, neatly 2,000 feet, when it met a counter current of air 

 from over the Coast Range, as evidenced by its di-ifting abruptly 

 away to the northeast. 



All this is a natural result of the topography of the country; 

 but what arrested my attention was a cloud of the cumulo-stra- 

 tus type, resting on the top of the column at the point of flexure, 

 like a cap. It did not appear to drift away, nor did it grow 

 larger or diminish, save that from its base it gave o£f a cloud of 

 the nimbus type, that mixed with the smoke and gradually in- 

 creased and extended, till, at about 10 o'clock p. m., it extended 

 across the northern horizon, like a dense rain cloud. Meanwhile, 

 other clouds began forming at sunset, and it ramed before morn- 

 ing. 



On Jan. 39, it cleared away, another fire was started, the 

 smoke rose in a column to the same altitude, struck the current, 

 and drifted away, no cloud forming. The same thing happened 

 on the 31st. On Feb 1, the apparent conditions were the same, 

 save a few clouds came in from the coast, but were soon dissi- 

 pated. In the afternoon I saw the fire start, and watched it. 

 The smoke rose as before, and struck the upper current of air. • 

 Immediately a cloud formed. In less than half a minute it had 

 reached its usual size, as large as the column, which it seemed to 

 cap. It was a dusty day, so the column was often broken. I 

 saw it blown from under the cloud, and a new one form three 

 times in about five minutes. 



I now noticed that, whereas the smoke drifted down the wind, 

 with its upper surface a horizontal plane, the liberated clouds as- 

 cended into the wind in the manner of a kite. Once outside the in- 

 fluence of the smoke, they were dissipated like the rest of the 

 clouds. General showers prevailed throughout the valley for the 

 next three days. 



Reasoning from my limited knowledge of physics, I might think 

 the cloud was caused by a column of heated and vapor-laden air 

 rising with the smoke, and being cooled by coming in contact 

 with the upper current, causing its vapor molecules to agglom- 

 erate into cloud particles ; but, for various reasons, I think this 

 inadequate. I have since seen the fires several times, with a 

 southerly wind, which generally brings our rain, but no cloud 

 formed. 



I have seen a theory advanced that vapor molecules need some 

 solid nucleus to start the process of agglomeration. Can any one 

 tell if this be so, and, if it is so, the rank that carbon takes as a 

 condenser ? 



I would also like to know why no cloud formed save in a 

 "chronic" state of the weather; and finally, why did the liber- 



