Oct. 14, 1880] 



NA TURE 



575 



' tlie adventures of a sportsman in Norway, supplies us in the 

 present sl<etch with a comprehensive rhumi of the flora of the 

 l'"jelds. The spot he has chosen for his point of observation is 

 ihe double topped hill Knudsho, near Kongsvold, well known 

 lo the botanists of other countries, as well as to those of Norway, 

 for its exceptionally rich and varied Alpine flora. Here may be 



) gathered the rare Artemisia norvegiea ; the gentians, nivalis 

 and glacialis ; some of the less common saxifrages, numerous 



[ species of Carex and Salix ; and some Alpine forms, as Kob- 

 resia caricina, Chaincurofes alpina, which are not found else- 

 where so low down ; while here, too, the collector will find close 

 at hand a number of sub-Alpine and south-Norwegian plants of 

 rare occurrence in other parts of the country. Ilerr Earth, 

 himself an enthusia.-tic botanist and a practised collector, never 



j fails to give the local and ordinary Norwegian name of the 

 plant he describes, in addition to its scientific designation ; and 

 thus supplies foreigners with very valuable and much-needed 



I information, the want of which often proves to be a matter of 

 great inconvenience in studying the flora of a foreign country. 



Om Grantorken og BarkbilUn. J. B. Earth.— In this little 

 pamphlet the author, who is one of the first authorities in 



j Norway on questions of forestry and arboriculture generally, 

 explains his reasons for differing from the opinion commonly 

 received, that the desiccation and ultimate death of the Norwe- 



i gian spruce (Abies exceha) are due to the attacks of Tomictts 

 typographus (Boslrychus typograp/ms), which is usually regarded 

 as tire most pernicious of all the insect-enemies of the Conifera;. 



' Herr Earth does not dispute the fact that this beetle is to be found 



' often in large numbers on trees affected by abnormal drying up, 

 whether still standing or cut down ; but, in his opinion, although 

 disease in the tree may be the cause, it is not the result of the 



' presence of the Tomicus, which he believes to have absolutely 

 no effect on the condition of the bark. According to this view 

 the numerous agents employed in Germany and elsewhere to 



I eradicate this beetle have no result but waste of labour and 

 money ; the only remedy against the drying up of the bark being 

 a more scientific mode of clearing forests, in which the trees 



I often perish either through overcrowding, or more frequently 

 through reckless felling, by which cold blasts are allowed to fall 

 directly on the interior. Herr Earth's views are in opposition 



i to those of the majority of the working foresters of Germany 

 and Scandinavia, but his extensive acquaintance with home and 

 foreign forests, his great practical experience, and his reputation 



J as a naturalist, entitle them to all possible respect, although it is 

 not to be supposed that his plea for the innocuousness of the 

 Boslrychus typographus will be admitted without much sifting of 

 the evidence, seeing that this insect is generally believed by 

 German foresters to have been the cause of the destruction of 

 the forests of the Harz Mountains, when between 17S0 and 1790 

 two million trees died of desiccation. 



SPECTROSCOPIC INVESTIGATIONS^ 



AS I have stated in my former communication,- all che- 

 mically related elements exhibit a homology of spectra, 

 li the various spectra of the elements of a group differing solely 

 J in the manner in which their groups of lines are shifted towards 



one end or other of the spectrum. 

 ' In a comparative investigation on the alkaline earths, I have 

 arrived at conclusions which may explain these remarkable 

 analogies in cliemically-related elements. 



I have now the honour of laying before the Academy a brief 

 account of my investigations ; on another occasion I shall report 

 on this subject more fully. 



If the spectra of the alkaline earths are produced by a jar- 

 spark in a hydrogen-atmosphere,^ spectra are obtained which 

 show the homology of the spectral lines very beautifully. The 

 spectrum of magnesium cannot be compared with the spectra 

 i obtained in this manner, becau.-e it does not c nitain the less 

 refrangible lines. However, without the jar, or employing a 

 smaller battery and a smaller induction-coil, it appears that in 

 the spectra of calcium and strontium all lines in the red and 

 yellow disappear, and the spectra which become visible are 

 remarkably similar to those of magnesium. 



" By G. Ciamician. in Sitz. Bcr. der k. Akad. dcr Wiss,, Vienna, Vol. 

 Ixxiv. Heft i. 



' " Ueber die Spectren der chemischen Elemente unj jhrer Verbin- 

 dungen" (vol. Ixxvi. chapter ii., (Jctober, 1877). "Ueber den Einfluss der 

 Dichte und der Teniperatur auf die Spectren von Dampfen und Gasen." 

 (vol. l.xxviii. chapter it., October, 1878) 



3 With four of six medium Bunscn's elements and a great Gaiffe's induc- 

 tion coil giving a spark of 10 centiiretrfs. 



Comparing the less refrangible part of the spectrum of the 

 alkaline earths, which are only rendered visible by increased 

 temperature with the less refrangible half of the entire oxygen 

 spectrum, we find the remarkable fact that these two halves 

 of the spectra show a decided resemblance or homology. 

 From this we may conclude that the spectrum of the groups of 

 the earth-alkali metals is composed of the spectrum of magnesium 

 and of that of the less refrangible parts of pxy^eti. 



In order to determine the real importance of these remarkable 

 analogies — it being known that the atomic weights of baryum, 

 strontium, and calcium are capable of being composed of the 

 atomic weights of magnesium and oxygen' — I found it necessary 

 to analyse the spectra of combinations, which are not saturated, 

 but behave as compound radicals, and thus most resemble in 

 chemical behaviour the simple radicals or elements. 



Hitherto I have analysed cyanogen and c:irbonic oxide. The 

 cyanogen spectrum comprises two portions, one of which is the 

 homologue of the nitrogen spectrum, the other the homologue 

 of the less refrangible part of the carbon spectrum. 



Also in the carbonic oxide spectrum there are present the 

 well-known groups of carbon appearing as bands, and displaced 

 in the red field there are several lines homologous to those of 

 oxygen. Therefore the same relation exists betsxeen the spectra 

 of nitrogen and carbon, and between the spectra of cyanogen, 

 carbon, .and oxygen, and carbon oxide spectrum, which prevails 

 between the spectra of magnesium and oxygen and the spectra 

 of the earth-alkali metals. 



One can go further and say that in general the homology of 

 the spectral lines of chemically-related elements is in all proba- 

 bility based upon the circumstance that the elements of such 

 natural groups conform to the laws of Mendelcjeff on atom- 

 weights, and consist of identical components. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Cambridge. — The Science Lectures at Cambridge this term 

 include Prof. Liveing on the General Principles of Chemistry, 

 and on Spectroscopic Analysis ; and Prof. Dewar on Physical 

 Chemistry. One of the demonstrators will give demontrations 

 in Volumetric Analysis ; and Mr. Scott, assistant to Prof. Dewar, 

 will give a course' of demonstrations in Elementary Organic 

 Chemistry. For permssion to carry out special investigations in 

 the University laboratories application should be made to one of 

 the Professors. 



Lord Rayleigh will lecture on Galvanic Electricity and Electro- 

 Magnetism in the Cavendish Laboratory ; Dr. Schuster will 

 lecture weekly on Radiation ; Mr. Glazebrook will give an ele- 

 mentary course of demonstrations in Electricity and Magnetism ; 

 and Mr. Shaw will give demonstrations on the Principles of 

 Measurement and the Physical Properties of B dies. Courses of 

 demonstrations are announced for the Lent Term on Heat and 

 Advanced Electricity and Magnetism ; and for the Easter Term 

 on Light, Elasticity, and Sound. 



Mr. W. |. Lewis will lecture on the Silicates, in the |Mine- 

 ralogical Lecture-room. 



Mr. F. M. Balfour will give elementary and advanced courses 

 on the Morphology of Invertebrata, with practical v\ ork. Prof. 

 Humphry will lecture on the Osseous System ; Prof. Hughes on 

 the Principles of Geology, with Field Lectures ; Prof. Latham 

 on Therapeutics ; Prof. Newton on Invertebrata ; Prof. Stuart 

 on Mechanism. 



It is to be hoped that something may be done this term to 

 relieve science students in the ma'ter of Greek, and to enc lurage 

 French and German studies, for want of which there is so much 

 hindrance to science, as well as literature. The Sedgwick Geo- 

 logical Museum, with money accumulatiii?, umst still wait, we 

 suppose. Will the Museum be ready for igoo? 



Mr. Sedley Taylor will lecture on the Acoustics of Music in 

 the Cavendish Laboratory. 



SCIENTIFIC SERIAIS 



Bulletins dela Societi! d' Anthropologic de Paris, tome iii. fasc. 2 

 (1880).— M. Robin, Inspecteur primaire du 1 'epartement de Loir- 

 et-Cher, has laid before the Society his scheme for obtaining 

 important anthropological measurei ents hy the help of teachers 

 of schools. The proposed questions, with a full description of 

 the various appliances by which such mea urements could be 



■ It is, namely, 24 -f 16 = 40 (calcium), 24 -I- 4 X 16 = 88 (strontium), 

 and 24 -I- 17 >; 16 = 136 (barium). 



