March 8, 1877J 



NATURE 



401 



logical Council to the Scottish Meteorological Society, as are 

 necessary for obtaining observations at stations required lor the 

 purposes of the Council ; for securi:ig the proper inspection of 

 stations the registers from which aie required for the general 

 purposes of the Council ; for the needful compilation and check 

 of such registers ; and for meeting other charges directly arising 

 from these services ; or for special researches couducted by the 

 Society with the approval of the Council ; but that no grants 

 should be made to ordinary observers, nor for any general pur- 

 poses of the society which lie beyond the scope of the operations 

 to be placed under the Council. 



23. We think that the same principle should be applied to all 

 similar local bodies interested in the study of Meteorology ; so 

 that, in fact, no payments should be made to them except for 

 results sought for by the Council. 



24. We have indicated above in very general terms the func- 

 tions of the proposed Council, and we do not think it desirable 

 to fetter their discretion by further details. We append, how- 

 ever, to this report a paper by a member of the present Com- 

 mittee of the Royal Society, who is also a member of our Com- 

 mittee, stating what, according to present experience, are, in his 

 opinion, likely to be their duties. 



25. The later stages of the inquiry in relation to the transfer 

 of oceanic meteorology to the Admiralty have raised some 

 serious questions of expense, which the Government wiil, 

 doubtless, require time to consider. We think it only just to the 

 Committee which has heretofore had the administration of the 

 annual grant to report our opinion that very good and valuable 

 work is being done by it, and that if funds were provided to 

 admit of the more responsible and more extended action of the 

 Council, as suggested in paragraphs 9 and 22 of our Report, and 

 if, at least provisionally, some assistance were given to the Scotch 

 Meteorological Society, the more immediate objects referred to 

 our Committee would be met, and there need be no inteiruption 

 of the Committee's operations pending the delay, if any, which 

 may occur, whilst the feasibility of transferring oceanic meteoro- 

 logy to the Admiralty is being maturely considered by her 

 Majesty's Government. 



It is important in connection with this part of the subject to 

 bear in mind the strong claims which the Superintendent and 

 other members of the existing staff have to continued employ- 

 ment. 



26. In recommending the above changes we feel bound to 

 express our sense of the great value of the disinterested services 

 which, at the cost of much time and labour have been rendered 

 during so many years by the Committee appointed by the Royal 

 Society. 



27. We are aware that what we are proposing is still tentative 

 only, and we recommend, in conclusion, that there shall be a 

 further inquiry and report at the end of (say) five years. 



RESEARCHES ON THE SPECTRA 

 METALLOIDS^ 



OF 



'X'illS paper was published by Mr. Thalen after Mr. 

 -'■ Angstrom's death. Mr. Thalen states, in the introduction, 

 that only the first sheet was printed during Mr. Angstrom's 

 life, who in the remainder would have liked to alter some 

 passages and add others. Yet we take it that such alterations only 

 would have referred to matters of detail, and that as far as 

 the general conclusions are concerned the paper represents fairly 

 Mr. Angstrom's opinion on the important questions discussed 

 therein. Mr. Thalen has made the measurements, while the 

 experiments were made by him in conjunction with Mr. 

 Angstrom. 



After a few histoiical remarks the authors give the following 

 judgment on the question of double spectra ; — 



" We are far from denying that the lines of an incandescent 

 gas may come out in greater number as the temperature, or per- 

 haps only the quantity of radiating matter increases, or that some 

 rays may increase much quicker than others in intensity. But it 

 is certain that the assertion of various physicists that the lines 

 originally seen may disappear altogether, and that in this way 

 the spectrum may change completely in appearance is as unlikely 

 from a theoretical point of view as it is contrary to experience. 

 If such properties were real all spectroscopic researches would 

 be rendered impossible as each element could play as far as its 

 spectrum is concerned the parts of a Proteus. 



' Abstract from a paper in the " Nova Acta Regis; Societatis Scientiarum 

 Upsaliensis," vol. ix., 1875, ''y A. J. Angstrom and T, R. Tlialen. 



" VVc do not deny that an elementary body may in certain 

 cases give different spectra. The absorption spectrum of iodine, 

 for instance, is quite different from its emission spectrum 

 obtained by means of the electric spark. All bodies existing in 

 different allotropic states will give different spectra correspond- 

 ing to these different allotropic states provided that the allotropic 

 states still exist at the temperature of incandescence. 



• . t • • • • 



" Oxygen, for instance, would present two different absorption 

 spectra, one belonging to oxygen the other to ozone. But as 

 ozone is destroyed at a high temperature, only one spectrum of 

 incandescent oxygen can exist. 



" Sulphur in the solid state exists in different allotropic states, 

 and some observations lead us to believe that even as a gas it 

 may exist in different states. Supposing this to be true, sulphur 

 will give us several absorption spectra, while the possibility of a 

 single or several emission spectra depends on the question 

 whether the more complicated allotropic states support the 

 temperature of incandescence. 



"It is evident that the above cases do not form an exception 

 to the general law which we have given, that an elementary 

 body can only give one spectrum. In fact, if we suppose that 

 the allotropic state is due to molecular constitution, it will possess 

 from a spectroscopic point of view, all properties of a compound 

 body, and in consequence it will be decomposed in the same 

 manner by the disruptive discharge of electricity." 



The paper then goes on to discuss the difference which is 

 noticed in the electric spark, between the aureole and the spark 

 ilsjlf. Messrs. Angstrom and Thalen sum up what they have 

 said on the subject in the following words : — 



1. There are two kinds of electric discharge, one of tension, 

 which takes place by explosion, or disruptively, the other of 

 quantity, which takes place by conduction, or continuously. 



2. By the disruptive discharge which always takes place when 

 the tension is sulfioiently great, the body is, as a rule, torn into its 

 smallest particles, and thus decomposed into its elements if the 

 body is compound. The phenomenon of incandescence which 

 accompanies both the mechanical disruption and chemical de- 

 composition, cannot be considered as a consequence of the aug- 

 mentation of temperature, but we ought rather to say that the 

 high temperature is an effect of the mechanical and chemical 

 force which disintegrated the body. In addition to the decom- 

 position produced directly by the disruptive discharge, we may 

 have chemical actions, which are, however, of a secondary nature. 



3. When the electricity is conducted by conduction we must 

 distinguish between two actions. We have actions which are 

 entirely due to heat, and which belong to the conductors them- 

 selves. They increase with the square of the intensity of the current. 

 We have, secondly, actions which make themselves perceptible 

 at the surface of bodies, and which are proportional to the in- 

 tensity of the current. These latter actions are confined in 

 elementary bodies to a variation in temperature, but if the body 

 is compound they may consist in chemical effects, which we call 

 electrolytic actions. These two phenomena, the Peltier effect 

 and the phenomenon of electrolysis, must be considered as dif- 

 ferent manifestations of the same force ; one or other of the 

 actions takes place according as the body is simple or compound. 



These laws, which are demonstrated to hold for solid and liquid 

 bodies, must also be applied to gaseous bodies, where we must 

 therefore expect electrolytic actions as well as chemical ones of a 

 secondary nature. 



Our authors then go on to discuss the spectra of carbon and 

 their compounds. They begin again with a historical statement 

 of the work done in this respect, and as this part of the papers 

 does not contain anything new to those who are interested in the 

 matter we pass to the question which they propose to solve : 

 "IIow are we to explain all these different spectra of carbon 

 compounds?" They draw attention to the fact that all these 

 spectra have a common characteristic, as they consist of bands 

 which can be resolved into fine lines. There is, however, one 

 spectrum which must be attributed to carbon, while the authors 

 attribute all other spectra to carbon compounds. This spectrum 

 is a line spectrum. It is obtained from carbon poles by means 

 of a powerful jar. ^ 



If we allow a spark to pass between carbon electrodes, the 

 lines are not seen in the middle of the field, but only close to 

 the poles similar to the metallic lines. If the discharge pass 

 through some carbon compaund, one obtains not only these car- 

 bon lines, but also those of oxygen, hydrogen, or nitrogen, that 



' It is the spectrum marked by Watts No. IV. — A. S. 



