March 12, 1886.] 



SCIENCE. 



239 



before the committee now investigating the sub- 

 ject. 



— The Abbe Laflamme. of the University Laval 

 at Quebec, has lately read an essay on the physi- 

 cal geography of the Saguenay, before the society 

 of geography in that city. He first describes the 

 actual geographic form of the district, and then 

 discusses its geological history, even from Ar- 

 chaean times, with special reference to the forma- 

 tion of the old limestones that lie in basins on the 

 crystalline rocks as an early chapter, and to the 

 glacial invasion as a later one. The present dis- 

 charge of Lake St. John is recognized as post- 

 glacial : the old outlet being more or less ob- 

 structed by drift, and in part occupied by Lake 

 Kenogami. The deep gorge of the lower Sag- 

 uenay is attributed to ordinary erosive action 

 through long geological periods; and the canon 

 of the Colorado is called recent in comparison 

 with it. 



— The programme for the first half of the course 

 of M eekly lectures at the national museum is as 

 follows : Saturday, March 6, Mr. William Hallock, 

 The geysers of the Yellowstone ; Friday, March 

 12. Prof. William Harkness, How the solar system 

 is measured ; Saturday, March 20, Prof. T. C. 

 Mendenhall, The nature of sound : Saturday, 

 March 27, Prof. F. W. Clarke, The chemistry of 

 coal ; Saturday, April 3, Dr. C. Hart Merriam, 

 The migration of birds. 



— The bill now before congress, providing that 

 from and after March 4, 1892, the metric system 

 shall be exclusively employed in the several de- 

 partments of the government, was favored by the 

 Boston society of civil engineers, at their meeting 

 the past week. 



— An account of a singular habit in the cicada 

 is related and illustrated by J. S. Newberry 

 in the School of mines quarterly. In Rah way. 

 N.J., a house had been built and a cellar dug in 

 an orchard some time before the appearance of a 

 brood of cicadas. The unused cellar was opened 

 about the time of their advent, and the bottom 

 was found to be thickly set with mud-cones or 

 tubes from six to eight inches high and an inch 

 or more in diameter, each of which had been 

 formed by the pupa of a cicada that had emerged 

 from the earth beneath the cellar. Finding a dark 

 chamber, and apparently desiring to work up to 

 daylight, the cicadas had taken the moist clay 

 and of this formed pellets, with which the tubes 

 were built up, apparently with the purpose of 

 bridging over the vacancy, and thus reaching the 

 surface. The tops of all were closed ; but, on 

 breaking some of them, the pupae were seen, both 

 in the hole in the ground and in the cone. After 



the cellar was opened, and light admitted, they 

 stopped building, and made holes in the tops of the 

 cones for exit. The author further remarks that 

 in these facts there is evidence of the exercise of 

 intelligence in the cicada, and a judicious adapta- 

 tion of means to an end in circumstances that, it 

 would seem, must have been without precedent in 

 the experience of that or any preceding generation, 

 and therefore for which no education of ancestors 

 could have given a preparation. It is possible 

 that the pupa of the cicada is sometimes embar- 

 rassed, in its ascent to the surface by water, by 

 too wet or too dry sand or mud ; but it is hardly 

 possible to imagine circumstances where the con- 

 struction of a tunnel would be necessary. There 

 seems to be no adequate explanation of the phe- 

 nomena that will bring them within the scope of 

 the theory according to which all our organs and 

 faculties are the result of formative influences 

 progressively developed through a long line of 

 ancestors. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good .faith. 



Bishop's ring during solar eclipses. 



The persistent visibility of Bishop's ring — the 

 dusky reddish ring around the suu — gives interest 

 to the following extract from Langley's ' Report on 

 the Mount Whitney expedition,' which recounts ob- 

 servations made at his camp, at an elevation of about 

 twelve thousand feet, on Aug. 19, 1881. "The sky 

 to-day, as always, is of the most deep violet-blue, 

 such as we never, under any circumstances, see 

 near the sea-level. . . . Carrying a screen in the 

 hand between the eye and the sun, till the eye is 

 shaded from the direct rays, it can follow this blue 

 up to the edge of the solar disk without finding in it 

 any loss of the deep violet or any milkiness as it 

 approaches the limb. ... It had been part of my 

 object to make an effort to see the solar corona by 

 directly cutting off the sun's light by a very distant 

 cliff. . . . On the south of the camp was a range 

 of cliffs running nearly east and west, and whose 

 perpendicular wall rose from one thousand to two 

 thousand feet. I found that I could choose a position 

 on the north of the cliff, along whose edge the sun 

 was moving horizontally ; so that the shadow was 

 fixed as regards the observer, and so sharp, that, 

 though I must have been over a quarter of a mile 

 from the portion of the cliff casting it, I could, with- 

 out moving my place, and by only a slight motion of 

 the head, put the eye in or out of view of the sun's 

 north limb. The rocks were, in these circumstances, 

 lined with a brilliant silver edge, due to diffraction. 

 This I had anticipated, but now I saw, what could 

 not be seen by screening the sun with a near object, 

 that the sky really did not maintain the same violet- 

 blue up to the sun, but that a fine coma was seen 

 about it of about 4° diameter, nearly uniform, 

 though it was sensibly brighter through the diameter 

 of Upon bringing to bear upon it an excellent 



portable telescope, magnifying about thirty times, I 

 found it was composed of motes in the sunbeam, be- 



