SCIENCE. 



[Vol. XVllI, No. 447 



without any condensation, and tlie other phenomenon re- 

 quiring a greater density in matter than exists in free space, 

 may, perhaps, receive other explanations that do less violence 

 to our ideas. Ether, in which the complex molecules of 

 matter are entangled, certainly might act as if it were more 

 dense without really being so. 



What the experiment of Michelson and Morley seems to 

 show is that the ether is swept along by the water, but lags 

 behind. The question of density appears to me still to be an 

 open one. Maxwell's experiment with a prism which was, 

 as was then supposed, moving through ether at a speed of 

 18.6 miles per second, seems to have a very different relation 

 to Fresnel's theory if the ether at the earth's surface is mav- 

 ing with it. 



It does not seem hopeless to repeat the experiment of 

 Michelson and Morley on a railway coach, with water or car- 

 bon bisulphide at rest in the tube, if the road-bed and the car 

 selected are of the best construction, and the apparatus is 

 elastically supported. 



It would be necessary, probably, to rigidly connect the ob- 

 server's seat and the water tube, and to support them, with 

 the observer, by helical steel springs surrounded by rubber 

 tubes filled with glycerine to dampen the vibrations. 



A speed of forty miles per hour will more than compensate 

 for the suppression of one water column, which will be re- 

 placed by air. This is precisely the form of experiment upon 

 which Eisenlohr's analysis is based. In this form the con- 

 ditions of the experiment are capable of great variation. 

 The car becomes really the moving body, and the transparent 

 region within through which the light passes, may be shielded 

 by any kind of opaque matter. Whatever the results may 

 be, they can hardly fail to add greatly to our knowledge of 

 the effect of moving masses upon the luminiferous ether. 



LETTERS TO THE EDITOR. 



*** Correapondeyits are requested to be as brief as possible. The writer's name 

 is in all cases required as proof of good faith. 



On request in advance., one hundred copies of the number containing his 

 comnntnication ii^iU -^e furnished free to any correspondent . 



The editor will be glad to publish any queries consonant with the charact<r 

 of the journal. 



Jugglery. 



In Science for Aug. 14 there was an inquiry, quoted from Illus- 

 trated News of the World, as to the source of a certain statement 

 regarding the apparently marvellous feats of Indian juga;lers. In 

 this statement it had been suggested that the spectators had been 

 hypnotized by the performer, and hence imagined they saw some- 

 thing which the "snap-shot" of a kodak proved did not exist at 

 all. I remember reading this very circumstantial account in an 

 evening paper, and cut it out to send to India. After some search 

 I have found the original reference. The story, as a quotation 

 from the Chicago Tribune, was published in the Evening Star of 

 Washington, D.C., on Aug. 30, 1890. Its author, Frederick S. 

 EUmore, purported to be a graduate of Yale College, and to have 

 travelled extensively in India with an artist friend, a Mr. Lessing. 

 It has since transpired that no person bv this name is a graduate of 

 Yale. 



To my mind the story shows a good many signs of being on the 

 Mulhatton style, and could easily have been written by some one 

 who had never been in India. It is very plain that no juggler 

 could by any possibility hypnotize a mixed audience all the time 

 changing. Those who have seen the original growth of the mango- 

 tree under the manipulations of the performer, who was stark 

 naked except for a lungooti (breech cloth), will be inclined to 

 smile at Hermann's explanation given in Science. My father 

 has spent twenty years in India, and has seen this performance re- 

 peatedly. He has noted one singular coincidence, in that the tree 

 is never made to grow except in the season when the leaves and 

 fruit of the mango-tree are in proper order for the exhibition. 



H. A. Hazen. 



Washington, D.C., Aug. 18. 



The Rain-Makers. 



Evert reader of Science has seen the recent telegram from Mid- 

 land, Texas, Aug. 11, "Preliminary explosions made yesterday; 

 raining to-day." It may be well, with the apparent brilliant suc- 

 cess of this remarkable undertaking before us, to examine this^ 

 question at length. 



Ever since the time of Plutarch the idea has been prevalent that 

 great battles are invariably followed by rain. In the earliest times, 

 before the introduction of gunpowder, it was thought that exha- 

 lations from the dead bodies might assist in precipitating the 

 moisture, but in more recent times there has been a well-nigb 

 universal belief among soldiers that heavy cannonading or firing 

 will produce rainfall. Whence comes this common thought were 

 there not a fact to originate and back it up ? We may as well 

 ask, whence comes the well-nigh universal belief that the moon 

 has a marked influence upon the weather ? No-v it is well known 

 that in the latter case, most careful researches extending over a 

 century have shown either no effect at all, or one that was either 

 contradictory in different periods, or almost inappreciable. 



Now since the moon's influence must be almost infinitesimal, as 

 every one can readily see, it would be difficult, perhaps, to deter- 

 mine its exact relation to weather changes which are so complex, 

 but it would seem far otherwise as to the determination of the 

 exact effect of explosions upon the atmosphere. A careful study 

 of this question has been made by Mr Edward Powers, who has 

 found that 158 of the smaller and larger battles of the Rebellioir 

 were followed by rain, usually twenty-four hours afterward. It 

 might be asked, is it possible that this list comprises all the cases? 

 While some of the battles may have been omitted, yet it seems 

 highly probable that a diligent search must have revealed most if 

 not all there were. It is a most remarkable fact that no mention 

 whatever is made of the battles that were not followed by rain, 

 and yet in an inquiry of this kind it is very essential to examine 

 both sides of the question. During the war of the Rebellion there 

 were over 3,300 battles, on an average probably as severe as the 

 average of the 1.58 above mentioned; that is to say, about seven 

 per cent of the battles were followed by rain. Is it at all incredi- 

 ble that seven per cent of these battles were followed by natural 

 rain? In the case of the battle of Bull Run, which Mr. Powers- 

 especially picks out as a bright and shining example of his theory 

 that explosions produce rain, it has been ascertained that there 

 was a heavy rain in South Carolina on the first day of the battle. 

 This rain had been previously noted farther south, and this was- 

 the rain felt at Bull Run. It would be very interesting to look 

 up the question of how many of these 158 apparent successes were 

 due to natural causes, but unquestionably almost all, if not all, 

 may be ascribed to that cause. It is interesting to note that it is 

 thought this influence may extend twenty -four hours after the ex- 

 plosions cease. This inference, however, is hardly tenable, for 

 the reason that the current in which these explosions take place is 

 borne along at the rate of 20, and, in higher strata, at 30, 40, 50, 

 and more, miles per hour, so that the specific influence from them 

 will be carried at least 500 miles away in twenty- four hours. If 

 we wished to determine the effect, we would need to go to that 

 distance from the spot where the explosions were made, and the 

 rain that came in twenty-four hours at that spot could not by any 

 possibility be due to the explosions. 



There is only one other point to be noted here. It has been 

 stated that while the Central Pacific Railroad was being built 

 across the Sierra Nevada Mountains, it was necessary to explode 

 himdreds of kegs of gunpowder every day, and this tremendous 

 fusillade was accompanied by torrents of rain, which had never 

 been noted before in that region, and have not been noted since. 

 If this is a fact, it was a most remarkable phenomenon, and it 

 would seem as though it might be established by indubitable evi- 

 dence. It is a little singular that no dates or definite statements 

 which could be verified have been given. Present rainfall reports 

 show an abundance of rain except in two or three of the hottest 

 months, and it seems entirely probable that persons who had been- 

 accustomed to the remarkable and long continued dryness of the 

 plains were struck by what appeared like most abundant moisture 

 in the mountains just at a time when there was none on the 

 plain. 



