i8o 



NA TURE 



[June 25, 1891 



in more usual parlance the rotation of the plane of polari- 

 zation under the action of magnetic force. It would be 

 hopeless to attempt to explain all the preliminaries of the 

 experiment to those who had not given some attention 

 to those subjects before, and he could only attempt it in 

 general terms. It would be known to most of them that the 

 vibrations which constituted light were executed in a 

 direction perpendicular to that of the ray of light. By 

 experiment he showed that the polarization which was 

 suitable to pass the first obstacle was not suitable to pass 

 the second, but if by means of any mechanism they 

 were able, after the light had passed the first obstacle, to 

 turn round the vibration, they would then »give it an 

 opportunity of passing the second obstacle. That was 

 what was involved in Faraday's discovery. [Experiment.] 

 As he had said, the full significance of the experiment 

 was not yet realized. A large step towards realizing it, 

 however, was contained in the observation of Sir William 

 Thomson, that the rotation of the plane of polarization 

 proved that something in the nature of rotation must be 

 going on within the medium when subjected to the 

 magnetizing force, but the precise nature of the rotation 

 was a matter for further speculation, and perhaps might 

 not be known for some time to come. 



When first considering what to bring before them he 

 thought, perhaps, he might include some of Faraday's 

 acoustical experiments, which were of great interest, 

 though they did not attract so much attention as his 

 fundamental electrical discoveries. He would only allude 

 to one point which, as far as he knew, had never been 

 noticed, but which Faraday recorded in his acoustical 

 papers. " If during a strong steady wind, a smooth flat 

 sandy shore, with enough water on it, either from the 

 receding tide or from the shingle above, to cover it 

 thoroughly, but not to form waves, be observed in a place 

 where the wind is not broken by pits or stones, stationary 

 undulations will be seen over the whole of the wet surface. 

 .... These are not waves of the ordinary kind, they are 

 (and this is the remarkable point) accurately parallel to 

 the course of the wind." When he first read that state- 

 ment, many years ago, he was a little doubtful as to 

 whether to accept the apparent meaning of Faraday's 

 words. He knew of no suggestion of an explanation of 

 the possibility of waves of that kind being generated 

 under the action of the wind, and it was, therefore, with 

 some curiosity that two or three years ago, at a French 

 watering-place, he went out at low tide, on a suitable day 

 when there was a good breeze blowing, to see if he could 

 observe anything of the waves described by Faraday. 

 For some time he failed absolutely to observe the pheno- 

 menon, but after a while he was perfectly well able to 

 recognize it. He mentioned that as an example of Fara- 

 day's extraordinary powers of observation, and even now 

 he doubted whether anybody but himself and Faraday 

 had ever seen that phenomenon. 



Many matters of minor theoretic interest were dealt 

 with by Faraday, and reprinted by him in his collected 

 works. He was reminded of one the other day by a 

 lamentable accident which occurred owing to the break- 

 ing of a paraffin lamp. Faraday called attention to the 

 fact, though he did not suppose he was the first to notice it, 

 that, by a preliminary preparation of the lungs by a number 

 of deep inspirations and expirations, it was possible so to 

 aerate the blood as to allow of holding the breath for a 

 much longer period than without such a preparation 

 would be possible. He remembered some years ago try- 

 ing the experiment, and running up from the drawing- 

 room to the nursery of a large house without drawing 

 any breath. That was obviously of great practical im- 

 portance, as Faraday pointed out, in the case of danger 

 from suffocation by fire, and he thought that possibly the 

 accident to which he alluded might have been spared had 

 the knowledge of the fact to which Faraday drew atten- 

 tion been more generally diffused. 



NO. I 1 30, VOL. 44] 



The question had often been discussed as to what would 

 have been the effect upon Faraday's career of discovery 

 had he been subjected in early life to mathematical train- 

 ing. The first thing that occurred to him about that, 

 after reading Faraday's works, was that one would not 

 wish him to be anything different from what he was. If the 

 question must be discussed, he supposed they would have 

 to admit that he would have been saved much wasted 

 labour, and would have been better en rapport with his 

 scientific contemporaries if he had had elementary mathe- 

 matical instruction. But mathematical training and 

 mathematical capacity were two different things, and it 

 did not at all follow that Faraday had not a mathematical 

 mind. Indeed, some of the highest authorities (and there 

 could be no higher authority on the subject than Maxwell) 

 had held that his mind was essentially mathematical 

 in its qualities, although they must admit it was not de- 

 veloped in a mathematical direction. With these words 

 of Maxwell he would conclude : " The way in which 

 Faraday made use of his idea of lines of force in co- 

 ordinating the phenomena of electric induction shows 

 him to have been a mathematician of high order, and one 

 from whom the mathematicians of the future may derive 

 valuable and fertile methods." 



THE ROYAL NAVAL EXHIBITION. 

 'T^HE Naval Exhibition, now being held at Chelsea, is 

 -*■ distinctly a popular show. The management — re- 

 cognizing that the first duty of an Exhibition is not to 

 show a pecuniary deficit— has wisely decided to follow 

 the lead given by Sir Philip Cunliffe Owen, and has 

 devoted the chief of its energies to fireworks, waxworks, 

 peep-shows, pictures, shooting-galleries, mimic sham 

 fights, and musical entertainments of a kind known 

 to sailors as " sing-songs."' The end justifies the means. 

 Not only does the Committee of distinguished Admirals 

 labour to supply Londoners with a cheap and innocent 

 means of enjoyment, but the final result will be the 

 establishment of a substantial fund to endow a most 

 deserving charity. Fortuitously there are features which 

 possess a more serious interest ; and though there may 

 be nothing especially new in the Exhibition, the man of 

 science who has not been brought much in contact with 

 naval matters may find there a good deal that is worth 

 consideration. 



The Exhibition appears to be divided into about half-a- 

 dozen sections, each under the direction of a committee. 

 Of these the "Entertainments" and "Refreshments" 

 Committees are of course the chief; but the Models Com- 

 mittee appears to be the one which has made the most 

 serious effort to present a distinctly naval subject in 

 logical sequence. In the Seppings Gallery there is a 

 collection of models of warships illustrating the progress 

 of naval architecture, from the Great Harry down to 

 the very latest design of armour-clad battleship. The 

 model of the Great Harry is of very doubtful authenti- 

 city, and is of modern construction, having been made by 

 the aid of such pictures of the great sixteenth-century 

 ship as exist. No historical collection of British war- 

 ships would, however, be even approximately complete 

 without a representation of this vessel. Charnock, our 

 great authority on the subject, has styled her "the 

 parent of the British Navy " ; and if it be true, as supposed, 

 that she was the first warship to sail on a wind, the claim 

 is most amply justified In fact, naval architecture as a 

 science was not founded until it was discovered that ships 

 could be, otherwise than by the aid of oars, taken to the 

 cjuarter from which the wind was blowing. It must have 

 seemed a great feat in those days— little less than necro- 

 mancy. Fortunately for the timid intellects of our 

 ancestors, the revelation broke upon them gently, for the 

 rounded hulls, high topsides, and curiously rigged craft 

 could not have sailed more than a point or two to wind- 



