Febkuary -21, 1903.] 



SCIENCE. 



349 



niauy interesting views of the dinosaur bones, 

 the quarries and the scenery of the region in 

 which they occur. T. C. Hopkins, 



Corresponding Secretary. 



UISCCSaiON AND CORRESPONDENCE. 



TUE FALL OF BODIES. 



The report of Professor E. H. Hall on the 

 motion of falling bodies recalls an interesting 

 experiment. It was proposed by Newton in 

 order to obtain a proof of the rotation of the 

 earth. The experiment was made by Robert 

 Hooke in 16S0. Hooke dropped a ball 27 

 feet, and it fell toward the east and south. 

 The most complete experiments have been 

 made in Germany. Benzenberg dropped balls 

 235 feet, and found a small deviation to the 

 south and a marked deviation to the east. 

 His first sixteen trials gave a deviation to 

 the north, but the last fifteen trials more than 

 balanced this. Two years later Benzenberg 

 repeated his experiments, and found a small 

 deviation to the north. It appears to have 

 been the erroneous investigation of this ques- 

 tion by Olbers that led Gauss to examine the 

 theory of this motion. Gauss says that, to 

 his astonishment, he found by theory no de- 

 viation to the south. Afterwards Laplace 

 examined this question (* Mec. Cel.,' Tome 

 IV.) and found no deviation to the south. The 

 most complete experiment is that of Professor 

 Reich, who dropped balls 488 feet. From 106 

 trials the deviation to the east was 23.30 mm., 

 and to the south 1.06 mm. 



The result appears to be that the deviation 

 to the east is decided, and that to the south 

 or north is so small that it can be ascribed to 

 errors of observation. The probable errors of 

 the results are large. Perhaps good condi- 

 tions for this experiment can be found in our 

 country. A. Hall. 



February 4. 100.3. 



JIOUXTAIN SPECTRE NEAR BOULDER, COLOR,\DO. 



The term ' mountain spectre ' is taken from 

 the Encyclopedia Britannica, where it is 

 noticed under the article ' Halo.' The best- 

 known example is at the Brocken in the Harz 

 Mountains. From the description of the phe- 

 nomenon as observed at that place, it is in- 



ferred that the appearance noted in Colorado 

 was quite as distinct as that at that famous 

 locality. It was observed February 1 from the 

 top of Green Mountain, near Boulder, Colo- 

 rado. This mountain is a high point in the 

 foothill belt; its summit is 2,500 feet above 

 the plains which it overlooks, or about 7,800 

 feet above the sea. On the day mentioned, 

 at 4:30 p.m. patches of white cloud were drift- 

 ing below its summit. Occasional snow flur- 

 ries visited the plains below. The tempera- 

 ture was apparently below the freezing-point. 

 At the hour of observation the sun, which 

 was not more than twenty degrees above the 

 horizon, was shining clear at the summit. 

 Opposite the sun, a few hundred feet distant, 

 was a mass of white or grayish cloud. Upon 

 this cloud was seen a complete circle of rain- 

 bow colors. The diameter of the most pro- 

 nounced red ring was estimated at nine de- 

 grees. Outside of this was a faint blue color, 

 and then a suggestion of red in a still larger 

 circle. Within the nine-degree red ring were 

 blue and violet, the center appearing a dull 

 lavender. In the field within the bright red 

 ring appeared the shadow of the observer, 

 which was so definite as to reproduce all 

 movements of arms and hands. Each ob- 

 server saw his own shadow and the reproduc- 

 tion of his owD. movements, and could see 

 nothing of the shadow or movements of his 

 neighbor if standing more than six or eight 

 feet away. The phenomenon was watched 

 about twenty minutes. 



N. M. Fenneman. 

 Univeksity of Colorado. 



signs of the glacial period in japan. 

 In my visit to Japan a few years ago I 

 failed to find any distinct signs of glacial 

 action, though I penetrated what seemed to 

 be a typical place for extinct glaciers in the 

 mountainous region one hundred miles north- 

 west of Tokyo. But Mr. Teijiro Ono, of the 

 Bank of Japan, has just sent me a translation 

 from a Japanese paper of some observations 

 in the mountainous district a little farther 

 south than that visited by me, which would 

 seem to indicate that there are some relics 

 of the glacial period in the central highlands 



