MISCELLANY. 



633 



on the contrary, the shoal is entirely broken 

 up, each fish taking an independent path, 

 and darting from one side of the tank to the 

 other with surprising agility. It was during 

 these active nocturnal movements that the 

 fish struck against the rockwork of the tank 

 and came to an untimely end ; this mortality, 

 however, was soon arrested by placing a 

 dim light over their tank, which illuminated 

 the outline of the rockwork just sufficiently 

 to enable them to recognize and avoid it. 

 With this dim light the fish still retained 

 their active habits, and it was noticeable 

 that during these night-hours they were 

 more than ordinarily alert for food, dashing 

 vigorously at any entomostracan or other 

 minute organism that passed through the 

 water. This circumstance would seem to 

 explain why " drift-net " fishing for herrings 

 can be carried on successfully only at night, 

 that being the time when the fish rise to the 

 surface of the water to feed on the innumer- 

 able organisms that there abound. 



Prof. Mayer on Sound. Prof. Mayer, 

 of the Stevens Institute of Technology, read 

 at the late meeting of the Academy of Sci- 

 ences a paper on the " Sensations produced 

 by Concurrent and Rapidly - succeeding 

 Sounds," a synopsis of which appears in 

 the Tribune. The author showed how cer- 

 tain sounds extinguish the sensation of oth- 

 er sounds. The rule appears to be that, 

 while low sounds cannot extinguish high 

 ones, high sounds may obliterate low ones. 

 He had been led to this course of observa- 

 tion by noticing that the click of a noisy 

 clock was, at certain intervals, silenced if a 

 watch was held to the ear. These intervals 

 of silence, he ascertained, occurred when 

 the sharp tick of the watch and the low 

 click of the clock were simultaneous. Then 

 by various and elaborate devices he satisfied 

 himself, not only of the general fact, but as 

 to what balancing of intensities was requi- 

 site. Prof. Mayer proceeded to demonstrate 

 the application of the rule to musical sounds. 

 This he made plain to the Academy by 

 means of apparatus producing a certain low 

 note from a wind-instrument simultaneously 

 with the same note several octaves higher 

 and of greater intensity. The high note 

 killed, so to speak, the low one. But, on 

 the other hand, a low note of great intensi- 



ty was powerless to extinguish a faint high 

 note : the high note utterly refused to be 

 drowned by any volume of the lower sound. 



Ancient Condition of Great Salt Lake. 



According to Prof. G. K. Gilbert, of Wheel- 

 er's Expedition, the Great Salt Lake of Utah 

 anciently had an outlet northward, the over- 

 flow being carried to the ocean by the Co- 

 lumbia River. But the Great Salt Lake was 

 then a great inland sea, as is evidenced by 

 the existence of an ancient beach 970 feet 

 higher than the Great Salt Lake of to-day, 

 and *700 feet higher than Sevier Lake. The 

 subsequent changes of level are described 

 as follows by Prof. Gilbert in the American 

 Journal of Science : " From the upper beach 

 the water slowly subsided by desiccation, 

 recording its lingerings in a series of fainter 

 shore-lines. When it had fallen to the level 

 of the divide between the Sevier and Salt 

 Lake Basins, it was separated into two un- 

 equal portions. In one of these the evap- 

 oration exceeded the inflow from rivers, and 

 the subsidence continued; in the other the 

 inflow exceeded the evaporation, and the 

 surplus was discharged over the divide into 

 the former portion, just as the surplus of 

 Utah Lake is now discharged into Great 

 Salt Lake. In the course of time, as the 

 climate became drier, this overflow ceased, 

 but not until it had carved a channel of 

 some magnitude. This channel is crossed 

 by the old overland stage-route, and is 

 known as the Old River-Bed." It is the 

 opinion of Prof. Gilbert that the humid cli- 

 mate which was marked by this inundation 

 of Utah was preceded by one as arid as the 

 present, and that the bumidity was a phe- 

 nomenon of the Glacial epoch. A fuller 

 statement and discussion of the facts will 

 appear in the forthcoming geological volume 

 of the " Reports of Wheeler's Surveys." 



Spontaneous Hypnotism. A case of 

 spontaneous hypnotism is described by Dr. 

 Bouchut in Les Mondes. A little girl of ten 

 had been apprenticed five months to the 

 business of making waistcoats. One day, 

 after a month of steady but not excessive 

 work, and while sewing a button-hole, she 

 became unconscious and slept for one hour. 

 On awaking, she resumed her work, but 

 with the same result. This hypnotism did 



