The Press. — London, England, 1855-09-15 00:00:00

886 out, and in giving to them a complete demon stration. But, to judge rightly Arago's genius, it seems to have been wanting in that imagina tive faculty which we have endeavoured to indicate. His name is not connected with any great original discovery. His was not an order of mind which advanced by leaps, but steadily, link by link. He was, as it seems to us, more remarkable for power of classification and analysis than for faculty of origination. There may be exceptions to this rule in the course of his long and arduous labours ;—we speak of the general character of his genius only, which was better fitted for carrying out and perfecting theories than for suggesting them. The mathematical and reasoning mind is most conspicuous in his works, his inventive power being shown chiefly in the subordinate capacity of devising means to illustrate prin ciples and extend their application. His faculties were often exercised in a purely judicial manner, but at the same time with admirable effect. His report on the case of a girl who it was asserted possessed extraordi• nary magnetic powers is a good example of his style of dealing with those pretended phe nomena which from time to time excite a stir in society. The Academy named a commis sion, with M. Arago at its head, to inquire into her case, and the following was his report : It was affirmed that Mademoiselle Cottin exercised a very intense repelling action on bodies of all kinds the moment they were touched by any part of her clothes. It was even said that stools were overturned by means of the simple contact of a silk thread. No appreciable effect of this kind was witnessed by the Commission. In the accounts communicated to the Academy, it is said that under the influence of this young person's arm, a magnetised needle first vibrated rapidly, and then came to rest at a considerable distance from the magnetic meridian. . . ________ In the presence of the Commission, a delicately-sus pended magnetio needle did not experience under these circumstances any displacement, either permanent or momentary. M. Tanchon thought that Mademoiselle Cottin possessed the faculty of distinguishing the north from the south pole of a magnet, by simply touching the two poles with her . _ fingers. The Commission assured themselves, by varied and nu merous experiments, that this young girl does not possess the supposed faculty of distinguishing the poles of a mag net by the touch. The Commission will not pursue further the enumera tion of failures ; its members content themselves with de claring, in conclusion, that the only one of the announced facts which was realised in their presence, was that of the sudden and violent movements in chairs in which the young girl sat. Serious suspicions had arisen as to the manner in which these movements were produced, and the Commission determined to subject them to an attentive examination. The Commissioners announced, without disguise, that their examination would be directed to dis cover what share certain skilful and concealed manoeuvres by the hands and feet might have had in the effect wit nessed by them. From this moment it was declared that the young girl had lost her attracting andrepelling faculties, and that whenever they should reappear we should be ap prised. Many days have since elapsed, and the Commis sion has received no such intimation. We know, however, that Mademoiselle tingelique Cottin is still daily presented in drawing-rooms, where she repeats her experiments. Wo quote this passage not only as an in stance of Arago's judicial capacity in scien tific matters, but because it suggests a mode in which some of our scientific societies might render themselves extremely useful. It is their part to examine novel phenomena, to determine what is real, to expose imposture, and to dispel popular delusion. But, un fortunately, that body which would bo best fitted for the exercise of such functions in England, the Royal Society, has degenerated from its original purpose, and become little better than a corporation for conferring a style which once was honorary as denoting real eminence in science and literature, but which is fast ceasing to be thought so, since it is now to be secured by connection, and purchased by money. In the essay on thunder and lightning, the general reader will readily recognise the justice of the praise we have given to M Arago for his diligence in collecting facts. The following may be new to some of our readers, and will appropriately introduce a few remarkable facts ,ou the effects of light ning : Yellow amber, when rubbed strongly, attracts light bodies, such as down or light feathers, straws, and sawdust. Theophrastus among the Ureeks, and Pliny among the Reset had remarked this property, bat without sp• THE PRESS. peering to attach to it more importance than they woull have done to any mere accident of form or colour. They had no idea that they had thus actually touched the first link in a long chain of discoveries. They failed to recog• nise the importance of an observation from which the moderns have drawn a whole world of facts, as curious by their singular character, as they are important in the results which have been deduced from them. They have been called electric phenomena, from the word ( /carol, by which the Greeks designated amber. - - • On the attractive power of :metals, it is re marked : Very numerous examples have proved that persons are never struck by lightning without its attacking more par- ticularly portions of metal woni by them. it may, then, be admitted that the danger of being struck is sensibly increased by metals attached to the person. Every one will be ready to admit this, where the metallic masses are at all considerable; I may mention that on the 21st of July, 1819, lightning fell on the prison of Biberach, in Swabia ; and that, in the great hall, amidst twenty prisoners, the one struck was the condemned chief of a baud of robbers, who was chained by the waist. In some instances lightning has entirely consumed metals with which it came in con tact:— The following fact, reported by Constantini in . 1749, is still more directly to the purpose. A lady was putting out her hand to close a window during a thunderstorm, the lightning darted, and the gold brace let which she wore disappeared altogether, so that no ves tige of it was found. She herself received only some very slight hurts. Without these preliminary remarksimy readers might have been surprised at my introducing here the explanation given by the celebrated traveller lirydone, of an accident which happened to a lady of his acquaintance, Mrs. Douglas. She was looking out of her window during a thunder storm, when a flash of lightning reduced her bonnet to ashes, without doing any other injury whatsoever. Mr. Brydone considered that the lightning had been attracted by the thin metallic wire supporting the front of the bonnet. Some curious cases are mentioned from which it seems probable that men resist the effects of lightning better than horses and dogs : On the 12th of April, 1781, Messrs. d'Aussac,de Gautran, and de Lavallongue, were struck by lightning near Castres. The three horses on which those gentlemen rode were killed on the spot. Only one of the riders, M. d'Aussac, perished. In June 1826, near Worcester, a mare led by a boy was killed by lightning; the boy was unhurt. In June 1810, Mr. Cowens was in a room with his dog by his side, when lightning entered the room ; the dog only was killed, Mr. Cowens barely felt. the shock. On the 11th of July, 1819, as already related, lightning killed nine persons out of the congregration assembled at Divine service in the Church at Chateau.Neufles•Moutiers ; but it was not added that several dogs which were in the church were all killed without exception. These animals were all found dead in the attitudes in which they were before the stroke. In one of his eloquent books Mr. Ruskin has a striking passage on the sublime impres sion of the Divine Power communicated to the mind of men by storms with com paratively little fatal consequence. This thought may be illustrated by M. Arago's researches. It is astonishing that so little damage should be done considering the amount of electric matter discharged by the clouds during a thunderstorm. By experi ments made on the Valentino Palace at Turin, it appears that the roof of this building alone, by means of its various conductors, took from the clouds each hour as much lightning matter as would suffice to kill three thousand persons. One of the most important chapters in the volume is that on the efficacy of lightning conductors. The remarkable exemption of the Temple at Jerusalem from damage by lightning is curiously explained:— We do not learn, either from the Bible or from Josephus, that the Temple at Jerusalem was ever struck by lightning during an interval of more than a thousand years—from the time of Soloman to the year 70,—although from its situation it was completely exposed to the very frequent and violent thunderstorms of Palestine. Remembering the care with which ancient nations recorded strokes of light- ning by which any degree of injury was done,—how often, for example, the Roman Annals mention the Capitol and other public buildings being struck by lightning,—it ap pears natural to infer from this silence, with the Orientalist Michaelis, that the Temple did not receive any severe stroke of lightning in the course of ten centuries. The probability of the justness of this inference is much strengthened by the circumstance that the Temple, being overlaid internally and externally with wood, would cer tainly have caught fire if struck by a violent thunderbolt. Supposing the fact to be thus well established, we have next, with Michaelis and Lichtenberg, to seek a cause, and we find a very simple one. By a fortuitous circumstance the Temple was armed with lightning-conductors quite similar to those which we now employ, and which we owe to Franklin's discovery. The roof, constructed in what we now call the Italian manner, and covered with beards of cedar having a thick SATURDAY, coating of gold, was garnished from end to end with long, pointed, and gilt-iron or steel lances, which Josephus said were intended to prevent birds from resting on the roof and soiling it. The walls also were overlaid throughout their extent with wood thickly gilt. Lastly, there were in the courts of the Temple cisterns into which the rain from the roof was conducted by metallic pipes. We have hero both the lightning-rods and a supply of means of conduc• tion so abundant, that Litchenberg is quite right in saying that many of our present apparatuses are far from offering in their construction so satisfactory a combination of ch• cumstances. _ _ . . _ The conclusion at which I arrive is, that the long immu- nity enjoyed by the Temple of Jerusalem presents the most manifest proof of the efficacy of lightning-conductors. Numerous details are given to show the efficacy of ordinary lightning-conductors in preserving buildings from injury during storms. the conductors should be pointed, as the electric fluid is thus more easily attracted. The whole phenomena of thunderstorms are so copiously treated by the author, and so fully illustrated by instances, that the essay is not only instructive in a high degree, but extremely amusing. Arago's application of Mr. Wheatstone's ingenious rotatory appa• ratus for determining the duration of the electric spark, to show how brief is the dura- tion of a lightning flash, is an example of that adaptative quality of his mind which we have indicated above. The result is shortly stated : We shall be keeping far within the conclusion which this experiment would authorise when we content our selves with saying that the most brilliant and extensive flashes of lightning of the first and second class, even those which appear to embrace the whole extent of the visible horizon, have not a duration equal to the thousandth part of a second of time. For the means by which this result is arrived at, without the possibility of error, we must refer to the volume itself. The ninth chapter—pages 4] to 48—is one of the most lucid and pleasing descriptions of a scientific experiment we ever met with. Mr. Wheat stone has, however, gone much farther, and demonstrated that the electric spark of our machines does not last the millionth part of a second. Arago's reputation is firmly fixed in Eng land, but his works are, with some excep tions, very little known, though emi nently deserving, from their copious matter and clear style, of extensive popularity. The series could not have opened with a more attractive volume, nor have we anything bat praise to bestow on the style in which it is presented to us. The complete edition of the works of Arago will be a most welcome ct,itri bution to our scientific literature. BURNETT PRIZE ESSAY. Christian Theism: the Testimony of Reason and .Revelation to the Existence and Character of the Supreme Being. By the Rev. R. A. Thompson, M.A. Two Vols. London: Rivingtons. WITHOUT depreciating the merits of this work, we may safely affirm that it never can be popular. Its usefulness must lie within a narrow circle. It is a metaphysical treatise, attempting to prove the existence and attri• butes of Deity from an analysis of the intel lectual constitution of man. In its general scope it resembles the essay of Professor Tulloch, which gained the second prize. It is more elaborate than that performance, and so far of higher merit, but neither more original nor more satisfactory. It is rather a lengthened review of all previous philosophical inquiry than the independent treatise of an origina. tive mind. It sets out with assuming that though it is highly probable that a belief in God is intuitive and entirely independent of all reasoning (i. 22), yet that we cannot prove the reality and grounds of such belief without investigating the principles of reason (i. 8-9.) That, therefore, we must begin with a knowledge of self, and inquire how it is that we come to distinguish between the ego and non-ego—between what is subjec tive and objective—between human con sciousness and the outward world (i. 23.4). This distinction pervades the whole essay. And, if we apprehend Mr. Thompson rightly, his main argument is that we arrive at a knowledge of Deity try exactly the same I