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THE POPULAR SCIENCE MONTHLY 



their surroundings. Experiments with artifi- 

 cial colors showed that both blue and red 

 tended to produce a dark coloration, espe- 

 cially the former ; while, strangely enough, 

 painted twigs did not produce the same ef- 

 fect as those whose tints were natural. Mr. 

 Poulton was able to show that the sensory 

 stimulus producing the change did not act 

 through the eye, as in the case of the chame- 

 leon, frog, and sole, but through the skin. 

 It consists, moreover, in the formation of 

 definite pigment, and hence is not so rapid 

 as in those animals. It is possible to modify 

 the color of a caterpillar only once or twice 

 in its lifetime. 



The past year, said Dr. Alexander Mac- 

 alister, in the anthropological address at the 

 British Association, had not been fertile in 

 discoveries bearing on questions of popular 

 interest. No new light had been shed on the 

 darkness that enshrouded the origin of man ; 

 but in this connection Dr. Louis Robinson 

 had, from a series of observations on the 

 prehensile power of the hands of children at 

 birth, arrived at the same conclusion which 

 Mr. Robert Louis Stevenson deduced from 

 the study of his grandfather — namely, that 

 there still survived in the human structure 

 and habit traces of our probably arboreal 

 ancestry. 



Op one hundred and three members of 

 the British Association of last year who 

 were antiiropometrically examined at Cardiff, 

 seventy-eight were men, and the mean stat- 

 ure of the whole was sixty-eight inches, 

 being one inch above the average stature of 

 the people of the British Isles. 



The third report of the committee of 

 the British Association to arrange for the 

 collection, preservation, and systematic regis- 

 tration of photographs of points of geologi- 

 cal interest says that, while the photographs 

 collected during the past two years are less 

 in number than those of the previous period, 

 a greater proportion are of high scientific in- 

 terest and illustrate features of real geologi- 

 cal importance. But considerable work is 

 yet required to be done toward the comple- 

 tion of a scheme for the full illustration of 

 the geological features of the United King- 

 dom. 



A preliminary account was read in the 

 British Association by Dr. Buchan of oceanic 

 circulation as deduced from the Challenger 

 observations. The author was convinced that 

 a thorough knowledge of the subject could 

 only be attained after a study of the prevail- 

 ing winds, as the currents followed the winds. 

 He then desc ibed the circulation of cur- 

 rents in the North Atlantic, and said that 

 these currents were lost at a depth of over 

 five hundred fathoms, below which point the 

 ocean had always a constant temperature at 

 all depths. The same condition was reached 

 at fifteen hundred fathoms in the Pacific 



Ocean. He went on to trace the course of 

 the warm dense salt water issuing below the 

 surface from the Mediterranean through the 

 Strait of Gibraltar. This, he said, traveled 

 northward, skirting the west coast of Europe, 

 and thus warming the water even to the north 

 of Norway. He considered that the current 

 was sufficiently warm and strong to prevent 

 the entrance of icebergs into the North Sea. 



The observations of dust in the air, made 

 eight times a day last year at the top of Ben 

 Nevis, showed well-marked variations in the 

 amounts present at different times of day. 

 Further, it was found that thick, dry fogs 

 contain a large amount of dust, whereas the 

 thin, wet mists contain little or none. 



In the course of his paper in the British 

 Association on the Application of Interfer- 

 ence Methods to Spectroscopic Measurement, 

 Prof. Michaelson, of America, found that the 

 results seemed to show that every line of 

 the spectrum is compound, though in many 

 cases the two components are very close 

 together, and have very unequal intensities. 

 The red line of oxygen has three distinct 

 components ; the red line of hydrogen is an 

 extremely close double, with nearly equal 

 components ; and the green line of cadmium 

 has two components, one of which is ten 

 times as intense as the other. 



In illustration of results obtained by the 

 Rev. T. J. Smith in inductoscript (writing by 

 induction currents), Mr. R. E. Baynes, in the 

 British Association, caused the spark of an 

 induction coil to be passed from a coin to a 

 photographic plate on which it was placed. 

 The plate was then developed, and showed 

 an image of the coin. On performing the 

 experiment in a vacuum no such result was 

 obtained. The effect could be got with bro- 

 mide paper as well as with plates. 



The American Association voted grants 

 of a hundred dollars each to Prof. Hart, for 

 investigations in chemistry ; to Prof. Joseph 

 Jastrow, in psychology ; and to the physical 

 table to be located at Naples. 



Describing, in the American Association, 

 the Prehistoric Earthworks of Henry County, 

 Ind., Mr. T. B. Redding said that there were 

 in that county ten curiously formed mounds, 

 surrounded by inclosures, and a number of 

 additional ones, though some of them are 

 not so evident as to be noticed by the casual 

 observer. There are also six inclosures in 

 which mounds do not appear. They may 

 have been obliterated. The mounds range 

 from twenty to a hundred and fifty feet in 

 diameter, and the inclosures are from a hun- 

 dred to two hundred and fifty feet in diame- 

 ter. Many of the mounds crumble away on 

 being exposed by taking off the turf cover- 

 ing, while others are in a good state of pres- 

 ervation. A number of relics and skeletons 

 were exhibited during the reading of the 

 paper. 



