June 5, 1879] 



NATURE 



137 



The statements, however, made in this table with regard to 

 the visibility of certain lines in the chromosphere do not appear 

 to be in accordance with Young's published tables, and as Messrs. 

 Liveing and Dewar have in a still later paper drawn theoretical 

 conclusions from these statements, I think it desirable to call 

 attention to the fact, in order to prevent any confusion which 

 might otherwise arise. 



It will be sufficient to refer to two cases. 



I. Messrs. Liveing and Dewar state that two lines of aluminium, 

 the wave-lengths of which they give as 6245 and 6237, have each 

 !)een seen by Voung eight times. 



According to Thalen's measurements, which are the best that 

 we possess, there are no lines of aluminium in these positions. 

 He gives, however, lines at 6244'o and 6234'o. 



Young, moreover, states that he saw reversed a strong line 

 (clearly shov.n in Angstrom's map to be an iron line) at 6245"4, 

 and a line which he does not ascribe to any element at 6237*3, 

 which is more than three divisions of the scale from the position 

 of the aluminium line. 



II. In the case of potassium, Messrs. Liveing and Dewar give 

 two lines at wave-lengths 4044 and 4042 as having been seen by 

 Young tlu-ee times. I know of no potassium lines at the places 

 given ; Young, moreover, has recorded the reversal of no potas- 

 sium line in this region. What Y'oung distinctly states he saw, 

 «as the reversal of the iron line at 4045 "o, which is one of the 

 most marked iron hnes in the spectrum of the sun. To this 

 reversal I referred in my paper of December 12.^ 



It is perfectly true that there are two potassium lines in this 

 region : they were not mapped by Thalen, and they were only 

 seen as a single line by Lecoq de Boisbaudran ^ and the wave- 

 length, given as 4045, as his dispersion was limited, did not 

 enable us to determine its true position with reference to the 

 Fraunhofer lines. 



Last year, however, I not only stated the double nature of 

 this line on photographic evidence,' and pointed out that both 

 components were absent from the spectre normal, but I gave 

 their wave-lengths as 404275 and 4046-28 (positions which 

 will only find the last place of decimals altered, even if it be 

 altered, in the revision of the map now being proceeded with), 

 and on the strength of them announced the existence of potassium 

 in the sun. Messrs. Liveing and Dewar do not state whence 

 their wave-lengths were derived, neither do they refer to my 

 communication. 



It would appear therefore not only that the reference to Young's 

 work in many cases is founded upon some misunderstanding, but 

 that a higher degree of accuracy than that employed by Messrs. 

 Liveing and Dewar is necessary to determine such coincidences. 



I may state generally that my eleven years' work on this special 

 branch has led me to the conclusion that all statements of coin- 

 cidences between metallic and solar lines with a lower degree 

 of accuracy than that employed by Thalen and Young are to be 

 avoided when possible, as they may be worse than useless, they 

 may mislead. Indeed, though the ^map on which I am workin;' 

 is on twelve times the scale of Angstrom's, it would be better 

 if it were larger ; and when I say this I must add my tribute of 

 admiration of the accuracy of the work of those who have 

 preceded me, notably Angstrom, Thalen, Cornu, and Young, 

 with whose work I am more ^familiar, as it [is expressed in 

 wave-lengths. 



May 29.—" Note on the Spectrum of Sodium," by T. Norman 

 Lockyer, F.R.S. 



I have lately been engaged in studying the spectrum of sodium 

 under new experimental conditions. In anticipation of a detailed 

 communication I take leave to state that the vapour given ofif 

 from the metal after slow distillation in a vacuum for some time 

 shows the red and green lines without any trace whatever of the 

 yellow one. Hydrogen is given off in large quantities, and at 

 times the C line and the red "structure" are seen alone. After 

 this treatment the metal, even when red-hot, volatilises with great 

 difficulty. 



Linnean Society, May i.— Lieut. -Col. Grant, C.B., vice- 

 president, m the chair.— Mr. Edw. S. Morris exhibited a quantity 

 of the berries, whole and ground, of the Coffca liberica, grown 

 by hun near Monrovia.— A living example of the rare and curious 

 Welmiischia mimbilis, reared at Kew, was shown and commented 

 on by Mr. \V. T. Thiselton Dyer.— The chairman also called 



' Proceedings, 191, p. 172. 



■ " Spectres Lumineux," texte, p. 48. 



3 Proceedings, No. 186, p. 280. 



attention to a series of the teaching diagrams illustratinir the 

 " Anatomisch-physiologischer Atlas der Botanik," now bein» 



issued by Dr. Arnold and Carolina Dodel-Port, of Zurich. A 



paper on nutrition in its relations to the fertilisation of flowers, 

 by Mr. Thos. Meehan (Philadelphia, U.S.), was read. His 

 observations chiefly refer to Wistaria sinensis, IV. frutescens, 

 Catalpa syringafolia, and Limina perenne, from which he de- 

 duces that the struggle for power between the growth or vege- 

 tative and the reproductive forces decides fertility. He further 

 suggests that the perfection of the polleniferous organs, and 

 consequent potency of pollen, is dependent on phases of nutri- 

 tion involved in this struggle. Thus in the above-mentioned 

 plants it is seen that potency in pollen — the main element in the 

 reproductive force — operates only when there has been some check 

 given to the force of vegetative growth. — The Rev. G. Henslow 

 read some remarks on Mr. Meehan's contribution, these in the main 

 supporting his views. He states, with regard to the different facts 

 and interpretation of experiments, that results however accurate 

 and true for one country may be very different for another, as has 

 been shown to be the case with Escholtzia. We cannot, therefore, 

 be too cautious in presuming that because a phenomenon may 

 invariably occur in our experience it must necessarily do so 

 everywhere and at all times. He recognises five degrees in the 

 effects of the reproductive force — 1. Entire abeyance when no 

 flowers are produced. 2. Flowers abundant, but pollen remains 

 a mass of tissue, as in Ranunculus ficaria. 3. Flowers pro- 

 duced with good pollen, but no seed set as in Escholtzia. 4. 

 Fruit produced only at definite places, as extremity of raceme, 

 or at definite periods, as late in summer. 5. Flowers and fruit 

 occur in abundance as in "tree" Wistaria, or freely growing 

 branches of \\y. — A paper on the structure of the Pouched Rats, 

 of the genus Hctcromys, by Dr. J. Murie, was read in abstract. 

 The anatomical structure and other peculiarities have been 

 \\orked out and a comparison with other forms given, alon» 

 with remarks on the sub-family Heteromyinoe generally. — The 

 Secretary read a note by Dr. M. Masters, on the occun-ence of 

 a Restiaceous plant in Cochin China, an interesting fact in the 

 geographical distribution of the group. — Messrs. T. E. Brown 

 (of Adelaide), Richd. Rimmer, and P. O. Shanessy (of Queens- 

 land), were elected Fellows of the Society, and two Foreign 

 Members were chosen to fill vacancies. 



Geological Society, May 14.— Prof. P. M. Duncan, F.R.S., 

 vice-president, in the chair. — The following communications 

 were read: — Further observations on the pre-Cambrian rocks of 

 Caernarvon, by Prof. T. M'Kenny Hughes, F.G.S. • The 

 author divides these into (l) the volcanic series, (2) the felsitic 

 series, (3) the granitoid series. He traces the former of these, 

 consisting of coarser and finer varieties, from Caernarvon to 

 near Port Dinorwig. Beyond these come the felsite series, 

 which is overlapped by grits and conglomerates as far as the 

 Bangor Road, north-east of Bri hdir. Above the latter comes 

 the " volcanic series," well developed in the neighbourhood of 

 Bangor. The author is of opinion that the Cambrian conglo- 

 merate, with associated grits, may be traced in the edge of the 

 older massif from Twt Hill, Caernarvon, to Garth Point, 

 Bangor, and that the beds in each of these places and near 

 Brithdir, recently described as separate, are identical ; also that 

 the bed with purple fragments near Tairffynnon and the Bangor 

 Poorhouse are only Cambrian conglomerate faulted down. Fur- 

 ther, he considers that the strata of the above three series are 

 fairly parallel throughout, and that they only form three sub- 

 divisions of one great series. — Notes on the structure of the 

 pala;ozoic districts of West Somerset, by A. Champernovvne, 

 F.G.S. , and W. A. E. Ussher, F.G.S. The authors confirmed 

 the general accuracy of Mr. Etheridge's views as to the structure 

 of North Devon and West Somerset, but differed from him in 

 ascribing the limestone of Cannington Park to the carboniferous, 

 both on account of lithological character, the fossils in Taunton 

 Museum, said to be obtained from it, and the latitude of its 

 position with reference to the carboniferous limestone of the 

 Mendip, South Wales, and the steep and flat Holmes. They 

 described four traverses made by them in West Somerset. I. 

 From Dulverton to Dunster, in which, proceeding northwards, 

 the following beds were encountered : — Culm-measures faulted 

 against Pilton Beds (upper Devonian), Pilton Beds faulted 

 against Pickwell-Down sandstone (base of upper Devonian), 

 Pickwell-Down sandstones becoming slaty in passing into Morte 

 slates (middle Devonian) and troughed in them by faulted syn- 

 clines, Morte slates passing into Ilfracombe slates (overlying 

 Hangman g^ts) near Cutcombe, Hangman grits, evidently 



