Febkuaky 16, 18S3.] 



SCIENCE. 



37 



observed. 5. Action of silver on iron. A 

 sliglit effect was produced. 



It will thus be seen, that the first experiment 

 described is the one which best exhibits tlie 

 influence of the magnet. The question still 

 remains, whether the striking effect observed 

 is due to the influence of magnetism on the 

 chemical action, or to some indirect influence 

 of the magnet. An examination of the liquid 

 while the action is going on shows clearly 

 that there are currents in it. Small particles 

 of dust, or any light material, on the surface 

 of the liquid, are drawn towards the poles, and 

 then move in circles above the poles, to the 

 right above one, to the left above the other. 

 We have hence electric currents in the liquid ; 

 and these revolve under the influence of the 

 magnet, as we would expect them to. This 

 action gi^'es rise to a streakj' condition of the 

 liquid, and this maj- possibly account for the 

 deposition of copper in the peculiar lines which 

 have*been described. I am nnable to saj' 

 whether this satisfactorily accounts for the 

 fact, that the lines of deposit are at right angles 

 to the lines of force ; but, as far as I have 

 been able to determine, it does not. Further, 

 if the presence of the currents is the cause of 

 the peculiar deposit of copper on iron, it would 

 appear that the same kind of action should be 

 observed whenever one metal i? deposited 

 upon another under the influence of a magnet. 

 This, however, is not the case, as was pointed 

 out above. The fact that the action takes 

 place markedl}' in the case of iron, and onlj' 

 very slightly, if at all, with other metals, sug- 

 gests, though it does not prove, that the action 

 is in some way connected with ttie magnetized 

 condition of the iron. Up to the present I 

 have been unable to experiment with cobalt 

 and nickel. Using nickel-plated brass, I did 

 not succeed in getting anv displacement of 

 other metals from solutions by nickel in this 

 condition. Experiments with these metals will 

 of course be of special interest. If it can be 

 shown that wnth them the same kind of action 

 takes place as with iron, and that with non- 

 magnetic metals it does, not take place, the 

 influence of magnetism directly on the chemical 

 action would be practically demonstrated. 

 The slight effects observed with other metals 

 akeadj- described maj^ possiblj- be attributed 

 to the presence of small quantities of iron in 

 the metals experimented upon. 



Turning from the I'idges of copper depos- 

 ited on the iron, what is the cause of the space 

 around the outline of each pole upon which 

 no copper is deposited? It is sharplj- deflned ; 

 and at the end of the operation it is bright, 



haAdng remained entirely unaffected by the so- 

 lution of copper sulphate. Here is evidently 

 a region, not by any means inconsiderable, in 

 which no chemical action has taken place. This 

 can hardly be ascribed to the presence of cur- ■ 

 rents in the liquid. The cause must, I think, 

 be looked for in the magnetized condition of 

 the iron; and I venture, though with misgiv- 

 ings, to suggest, that, the influence of the mag- 

 netism being most stronglj^ felt in the iron at 

 the outlines of the poles, these parts of the 

 iron resist the action of the copper sulphate. 

 We may imagine, that the molecules of iron in 

 the regions immediatelj* surrounding the poles 

 are held more flrmly than those which are less 

 directlj' under the influence of the magnet, 

 and that the interference with their motion 

 protects them. Just as, in general, any cause 

 which facilitates the motion of molecules fa- 

 cilitates chemical action, so, also, any cause 

 which interferes with the motion of molecules 

 would probablj' prevent chemical action either 

 completelj- or partiall}-. I recognize the crude- 

 ness of this suggestion. If there are any ob- 

 jections which can be raised against it, I shall 

 be glad to be informed of them. In the mean 

 time it may at least serve as a working hj-- 

 pothesis, and may lead eventually to a more 

 satisfactory' view. I intend to continue ex- 

 periments on the subject under consideration. 

 Unfortunatel}', the phenomena which can aid 

 in the solution of the problem appear to be but 

 few, and these do not readily lend themselves 

 to quantitative treatment. The work will ne- 

 cessarily advance slowlj^ but I shall continue 

 it as long as there appears to be an^ hope of 

 setting results of value. Ira Kemsen. 



ROTIFERA WITHOUT ROTARY ORGANS. 



Pkofessor Joseph Lbidy, in a j^aper recently 

 published in the Proceedings of the Academy of 

 natural sciences of Philadelpliia, observes that tlie 

 Rotifera, or wlieel-animalcules, form a smaU class, 

 abundant in kind, and found almost everywhere in 

 association with algae and -with infusorians to which 

 they were formerly considered to belong. Later they 

 were regarded as crustaceans, but now are looked 

 upon as belonging to the group of worms. Their 

 usual striking characteristic, the rotary disks, is not 

 possessed by any well-marked crustacean. Among 

 the Eotifera, however, there appear to be some which 

 do not possess the rotary organs, and yet in all other 

 respects conform in structure to ordinary forms. 



IDuiardin, Gosse, and Claparede have described 

 rotifers which they regarded as destitute of rotary 

 organs: but Cohn described one with these organs, 

 otherwise resembling the form of Dujardin, and sus- 

 pects that the latter made a mistake; and remarks 

 that thfe existence of a rotifer without vibratile cilia 

 would be an abnormal condition in the class. While 

 the forms described by the three authors above named 

 are open to the suspicion that they may possess ro- 

 tary organs which were withdrawn at the time of 



