August 4, 1892] 



NATURE 



327 



suggest to us the solution of many mysteries which are now 

 puzzling us. Consider, for instance, how long it would have 

 taken to prove the universal property of gravitational attraction 

 if the record of planetary motion had not come to the philoso- 

 pher's help. And surely the most casual observation of cosmical 

 effects teaches us how much we have yet to learn. 



The statement of a problem occasionally helps to clear it up, 

 and I may be allowed, therefore, to put before you some ques- 

 tions, the solution of which seems not beyond the reach of our 

 powers. 



1. Is every large rotating mass a magnet? If it is, the sun 

 must be a powerful magnet. The comets' tails, which eclipse 

 observations show stretching out from our sun in all directions, 

 probably consist of electric discharges. The effect of a magnet 

 on the discharge is known, and careful investigations of the 

 streamers of the solar corona ought to give an answer to the 

 question which I have put.^ 



2. Is there sufficient matter in interplanetary space to make 

 it a conductor of electricity ? I believe the evidence to be in 

 favour of that view. But the conductivity can only be small, 

 for otherwise the earth would gradually set itself to revolve 

 about its magnetic pole. Suppose the electric resistance of 

 interplanetary space to be so great that no appreciable change 

 in the earth's axis of rotation could have taken place within 

 historical times, is it not possible that the currents induced in 

 planetary space by the earth's revolution may, by their electro- 

 magnetic action, cause the secular variation of terrestrial mag- 

 netism ? There seems to me to be here a definite question 

 capable of a definite answer, and as far as I can judge without 

 a strict mathematical investigation the answer is in the affirma- 

 tive. 



3. What is a sunspot? It is, I believe, generally assumed 

 that it is analogous to one of our cyclones. The general appear- 

 ance of a sunspot does not show any marked cyclonic motion, 

 though what we see is really determined by the distribution of 

 temperature and not by the lines of flow. But a number of 

 cyclone-; clustering together like the sunspots in a group should 

 move round each other in a definite way, and it seems to me 

 that the close study of the relative positions of a group of spots 

 should give decisive evidence for or against the cyclone theory. 



4. If the spot is not due to cyclonic motion, is it not possible 

 that electric discharges setting out from the sun, and accelerat- 

 ing artificially evaporation at the sun's surface, might cool those 

 parts from which the discharge starts, and thus produce a sun- 

 spot ? The effects of electric discharges on matters of solar 

 physics have already been discussed by Dr. Huggins. 



5. May not the periodicity of sunspots, and the connection 

 between two such dissimilar phenomena as spots on the sun and 

 magnetic disturbances on the earth, be due to a periodically 

 recurring increase in the electric conductivity of the parts of space 

 surrounding the sun? Such an increase of conductivity might 

 be produced by meteoric matter circulating round the sun. 



6. What causes the anomalous law of rotation of the solar 

 photosphere ? It has long been known that groups of spots at 

 the solar equator perform their revolution in a shorter time than 

 those in a higher latitude ; but spots are disturbances which may 

 have their own proper motions. Duner- has shown, however, 

 from the displacement of the Fraunhofer lines, that the whole of 

 the layer which produces these lines follows the same anomalous 

 law, the angular velocity at a latitude of 75° being 30 per cent, 

 less than near the equator.' As all causes acting within the sun 

 might cause the angular velocity of the sun to be smaller at the 

 equator than at other latitudes, but could not make it greater, 

 the only explanation open to us is an outside effect either by an 

 influx of meteoric matter, as suggested by Lord Kelvin, or in 

 some other way. If we are to trust Dr. Welsing's result, that 

 facula: which have their seat below the photosphere revolve in 

 all latitudes with the same velocity, which is that of the spot 

 velocity in the equatorial region, we should have to find a cause 

 for a retardation in higher latitudes rather than for an accelera- 

 tion at the equator. The exceptional behaviour of the solar 

 surface seems to me to deserve very careful attention from solar 



' The efforts of Mr. Bigelow have a bearinjp; on this point, also some 

 remarks which I have made in a lecture before the Roval Institution 

 (Proc. Roy, Inst. 1891), but nothing decisive can be asserted at present. 



^ Oefvers. af Kongl. Veterrk. Ak. Forhandl., 47, 1890. 



3 Although the imfiortance of M. Duner's results would make an inde- 

 pendent investigation desirable, the measurements of Mr. Crew, who by a 

 much inferior method arrived at other results, cannot have much weight as 

 compared with those of Duner. 



NO. Hi 



VOL. 



46] 



physicists. Its explanation will probably carry with it that of 

 many other phenomena. 



In conclusion, I should like to return for an instant to the 

 question whether it is possible by any means to render the pro- 

 gress of science more smooth and swift. If there is any truth 

 in the Idea that two types of mind are necessary, the one cor- 

 responding to the bailer and the other to the cooler of a steam- 

 engine, it must also be true that some place must be found where 

 the two may bring their influence to bear on each other. I ven- 

 ture to think that no better ground can be chosen than that 

 supplied by our meetings. We hear it said that the British 

 Association has fulfil'ed its object: we are told that it was 

 originally founded to create a general interest in scientific prob- 

 lems in the towns in which it meets ; and now that popular 

 lectures and popular literature are supposed to perform that 

 work more satisfactorily, we are politely asked to commit the 

 happy despatch. There is no need to go back to the original 

 intention of those who have founded this institution, which has 

 at any rate adapted itself sufficiently well to the altered circum- 

 stances to maintain a beneficial influence in scientific research. 



The free discussion which takes place in our sections, the inter- 

 change of ideas between men who during the rest of the year 

 have occupied their minds, perhaps too much, with some special 

 problem, the personal intercourse between those who are begin- 

 ning their work with sanguine expectations, and those who have 

 lost the first freshness of their enthusiasm, should surely one and 

 all ensure a long prosperity to our meetings. If we cannot 

 claim any longer to sow the seeds of scientific interest in the 

 towns we visit, because the interest is established, we can at any 

 rate assure those who so kindly offer us hospitality that they are 

 helping powerfully in the promotion of the great object which 

 we all have at heart. 



SECTION B. 



CHEMISTRY. 



Opening Address by Prof. Herbert McLeod, F.R.S., 

 F.C.S., President of the Section. 



In endeavouring to prepare myself to properly fulfil the duties 

 of President of this Section, to which I have been elected, and for 

 which honour I am much infiebted to the council and members 

 of the Association (although I am only too well aware that the 

 position might have been more efficiently filled by many others), 

 I naturally looked at the reports of the previous meetin^js held 

 in Edinburgh in 1834, 1850, and 187 1, and it appears that on 

 the first two occasions an address was not given by the president, 

 a custom the discontinuance of which I have, at the present 

 moment, much reason to regret. 



At the meeting in 1834 a committee was appointed consisting 

 of Dr. Dalton, Dr. Hope, Dr. T. Thomson, Mr. Whewell, 

 Dr. Turner. Prof. Miller, Dr. Gregory, Dr. Christison, Mr. R. 

 Phillips, Mr. Graham, Prof. Johnston, Dr. Faraday, Prof. 

 Daniell, Dr. Clark, Prof. Gumming, and Dr. Prout, to report 

 at the next meeting their opinion on the adoption of an uniform 

 set of chemical symbols. Dr. Turner to be secretary'. 



In the following year the report contains: "Report of the 

 Committee on Chemical Notation. Dr. Turner, the chairman 

 of the committee appointed to take into consideration the adop- 

 tion of an uniform system of chemical notation, made fi. report 

 to the following effect : — 



"I. That the majority of the Committee concur in approv- 

 ing of the employment of that system of notation which is already 

 in general use on the Continent, though there exists among them 

 some difference of opinion on points of detail. 



'• 2. That they think it desirable not to deviate in the manner 

 of notation from algebraic usage except so far as convenience 

 requires. 



"3. That they are of opinion that it would save much con- 

 fusion if every chemist would always state explicitly the exact 

 quantities which he intends to represent by his symbols. 



" Dr. Dalton stated to the Chemical Section his reasons for pre- 

 ferring the symbols which he had himself used from the com- 

 mencement of the atomic theory in 1803, to the Berzelian sys- 

 tem of notation subsequently introduced. In his opinion regard 

 must be had to the arrangement and equilibrium of the atoms 

 (especially elastic atoms) in every compound atom, as well as to 



