194 



NATURE 



\_Dec. 25, 1879 



of the mercury lines. But an amalgam of bismuth gave readily 

 the reversal of the bismuth line, wave-length 4722, and with 

 more difficulty that of the line, wave-length 41 19. 



Antimony did not appear to give any lines, or none easily dis- 

 tinguishable, in the arc. 



With copper the reversal of two lines only were observed, 

 wave-length 5105, 5'53- 



Iron introduced as metal, or as chloride, in the usual way, 

 gave no reversal ; with an iron rod used as positive pole instead 

 of one of the carbons, the authors succeeded in getting the 

 reversal of one line, wave-length 4045, which expanded and 

 showed a fine dark line in its middle ; but by passing an iron 

 wire into the arc through the positive carbon, which was per- 

 forated, and pushing in the wire slowly as the end burned away, 

 several of the brightest of the iron lines were reversed. The 

 three violet lines, wave-lengths 4045, 4063, 4071, were the first 

 to be reversed. They all expanded before showing reversal, and 

 the order of reversal was that of refrangibility. Besides these 

 seven other of the brightest lines were reversed. 



Nickel, whether put into the crucible in the old way, or fed 

 into the arc in small fragments filling a platinum tube which was 

 passed through a perforated carbon pole, gave no definite reversal 

 of any of its lines ; nor did cobalt, even when a bar of cobalt 

 was used as the positive pole. 



Tin, palladium, and platinum gave no reversals. 



It is worthy of remark in regard to the difficulty of obtaining 

 substances chemically pure that the authors found that carbon 

 poles which had been for some hours ignited in a current of 

 chlorine and further intensely heated in the arc, while a current 

 of chlorine was passed through perforations down their axes, still 

 showed in the arc, of course without any crucible being employed, 

 a multitude of lines amongst which the so-called carbon lines and 

 those of calcium and iron were conspicuous. 



December 18. — " On the Capillary Electroscope," by G. Gore, 

 LL.D., F.R.S. 



This paper contains a description of a modified form of the 

 "Capillary Electroscope," together with full details of its con- 

 struction and of the circumstances which affect its successful 

 action. Numerous forms of the apparatus were constructed 

 and a variety of solutions employed with the hope of obtaining 

 an instrument capable of being employed for accurate measure- 

 ments of feeble electromotive forces, but without success. The 

 author is now engaged in examining the behaviour of a variety 

 of liquids in the apparatus, and in completing an investigation of 

 the causes and conditions of the movements. During this 

 examination he has discovered the singular circumstance that in 

 certain cases the mercury moves in an opposite direction to the 

 electric current. 



Mathematical Society, December 11. — C. W. Merrifield, 

 F.R.S., president, in the chair.— The following gentlemen were 

 elected members : — Mr. W. Burnside, Mr. J. R. Harris, Dr. \V. 

 Jack, Mr. W. J. Curran Sharpe, and Prof. W. Woolsey Johnson, St. 

 John's College, Annapolis, Maryland. — The following communi- 

 cations were made to the Society : — Note on a method of 

 obtaining the ^-formula for the sine-amplitude in elliptic func- 

 tions, by Mr. J. W. L. Glaisher, F.R.S. — Note on a numerical 

 theorem connected with the cubical division of space, by the 

 President. — Notes on Curvature, by Mr. J. J. Walker. — A 

 property of a linkage, by Mr. A. B. Kempe. — Mr. Merrifield's 

 note arose thus : — it is known that if space be cubically divided 

 by three systems of orthogonal and equidistant planes, there 

 must be an infinite number of ways of selecting points of the 

 system, which shall be the corners of cubes obliquely placed and 

 the theorem (infra) shows that the edges of such cubes will 

 be commensurable with the unit of the system. Take 

 A — O B = C, orthogonal to one another, and the co- 

 ordinates of A, B, C referred to rectangular axes, rational 

 numbers, it is shown that the length A = OB— OC is also a 

 rational number. If l y m 1 », ; / 2 m t »» ; l 3 m 3 n 3 are the co- 

 ordinates of A, B, C respectively, then we have — 



/ s l 3 + m 2 m 3 + >u n 3 - o, 

 and two other like equations. Also if 



h 



11. 



-84 1 

 4 7 4 

 1 4 -8 



-9 6 2 

 676 

 26 -9 



r = 25, 



•19 8 4 



8 11 16 



4 16 -13 



9 12 -20 

 12 16 



-20 15 



15 



then (!." + »if 4 « 2 2 ) (/ 3 e + « 3 S + u 3 -) = ^(If + ;«, 2 + »r), or 

 O B* . C* = r^ A-. Therefore if any two of the three lines 

 O A, OB, O C are equal, the third is rational. A few numerical 

 examples are given : — 



Values were also given for r = 19, 23, other values proved 

 refractory. If the above are read as determinants, the groups 

 are all symmetrical, 9, 11, 19 being symmetrical about both 

 diagonals. The value of the determinant is always ± r 3 as it 

 should be, being simply the volume of the cube of which r is an 

 edge. Mr. Glaisher pointed out that the diagonal about which 

 there is symmetry has the sum of its terms = ± r. The reason 

 for this and why there should be symmetry, is not so apparent. 



Geological Society, December 3. — Henry Clifton Sorby, 

 F.R. S., president, in the chair. — Syed Ali, Wynne Edwin Baxter, 

 Arthur Robert Boyle, Rev. John Lowry Carrick, M.A., Prof. 

 Edward Waller Claypole, Rev. T. Dowen, Rowland Gascoyne, 

 George M. Henty, John Marshall, Josiah Martin, Charles Maxtec?, 

 Edward Provis, Thomas William Rumble, Rev. John Reuben 

 Taft, Octavius Albert Shrubsole, Samuel Richard Smyth, and 

 William Neish Walter were elected Fellows of the Society. — The 

 following communications were read : — The gneissic and granitoid 

 rocks of Anglesey and the Malvern Hills, by C. Callaway, 

 F.G.S., with an appendix on the microscopic structure of some 

 of the rocks, by Prof. T. G. Bonney, F.R.S., Sec.G.S. The 

 author described the results of his investigations into the strati- 

 graphy and petrology of the above districts, which have led him 

 to the following conclusions : — I. The granitoid (Dimetian) rocks 

 of Anglesey pass down into an anticlinal of dark gneiss (above) 

 and grey gneiss (below). 2. Associated n ith the granitoid series 

 are bands of felsite, halleflintas, and felspathic breccias. 3. The 

 succession of gneissic and granitoid rocks in Anglesey resembles 

 so closely the metamorphic series of Malvern as to justify the 

 correlation of the two groups. 4. The pre-Cambrian rocks of 

 Anglesey and the Malverns, from the highest known member 

 down to the base of the gneiss, may be thus classified : — A. 

 Pebidian(to be described hereafter) ; B.Malvernian; (a) Dime'.ian, 

 with associated quartz-felsites and halleflintas (Arvonian) pas-ing 

 down into (li) Lewisian. — Petrolngical notes on the neighbour- 

 hood of Loch Maree, by Prof. T. G. Bonney, F.R.S., Sec.G.S. 

 The author described the microscopic structure of a typical series 

 of the Hebridean gneiss, and gave reasons for considering the 

 mass of rock on the right bank of Glen Laggan to be not an 

 intrusive " syenite," as has usually been supposed, but a mass of 

 the Hebridean gneiss faulted against the newer series. By 

 examination of specimens, collected both in Glen Laggan and at 

 other points along the northern escarpment of the newer series, 

 the author showed that its rocks have been rightly called meta- 

 morphic ; and then, b/ comparison of these with specimens col- 

 lected in Glen Docherty, he concluded that the latter belonged to 

 the newer series, and that no part of the Hebridean series reap- 

 peared here. — On some undescribed Comatula; from the British 

 secondary rocks, by P. Herbert Carpenter. 



Zoological Society, December 16. — Prof. Flower, F.R.S., 

 president, in the chair.— Mr. H. Seebohm exhibited and made 

 remarks on a collection of birds made by Captain the Hon. G. 

 C. Napier, in the valley of the Atreck, near the south-east corner 

 of the Caspian Sea. — Mr. R. G. Wardlaw Ramsay exhibited a 

 specimen of Pericrocotus flammeus in an abnormal state of 

 plumage, obtained on the Neilgherry Hills in Southern India.— 

 Mr. Sclater exhibited a small collection of birds from the Island 

 of Montserrat, West Indies, received from Mr. J. E. Sturge, of 

 that island. This collection, though small, was of much interest, 

 as nothing was previously known of the ornithology of Mont- 

 serrat. — Mr. T. J. Parker read a paper on the intestinal 

 spiral valve in the genus Rata. Mr. Parker showed that there 

 were four types of valve exhibited in individuals of that genus, 

 differing from one another in morphological characters, in the 

 extent of absorption surface presented to the food, and in the 

 resistance offered to the passage of food. — A communication was 

 read from the Marquis de Folin on the mollusca of the Challenger 

 Expedition of the genera Parasirophia, Watsonia, and Ctecum. — 

 Prof. W. H. Flower, F.R.S., read a communication on the 

 caecum of the Red Wolf (Cants julwtus), in which it was shown 

 that that animal differed from the majority of the Caititk in 

 possessing a very short and perfectly straight caecum. — A com- 

 munication was read from Mr. Edward Bartlett containing a list 

 of the mammals and birds collected by Mr. Thomas Waters in- 



