Natural- Philosophical Collections'. 303 



known.) A revolving or circulating motion also appears in the oil, carrying the 

 alcoholic globules through a series of mutual attractions and repulsions, — the 

 round bodies moving freely through the fluid, turning short in a small eccentric 

 curve at each extremity of their course, passing each other rapidly without touch- 

 ing ; but after a time, they seem to acquire a density approximating to that of 

 the lower stratum, which appears to be an aqueous portion, separated by the 

 ethereal oil from the alcohol ; and this assimilation taking place, the globules, 

 after performing many revolutions, will fall flat upon the surface, and unite with 

 the lower or watery stratum. 



The orbits of those small globules being confined by the glass are very eccen- 

 tric. In the course of the experiment, I observed particles of the fluid to separate 

 in larger globular portions ; these commenced a similar revolution, and smaller 

 ones quitted their course and revolved about the larger, whilst the latter still pur- 

 sued their course after the manner of primary planets and their secondaries. This, 

 however, can only be well understood by seeing the experiment, which is easily 

 performed, and well worth the trouble ; as it appears to me, that, if attentively 

 studied, it might furnish important deductions, and serve, we know not how far, 

 towards an illustration of the celestial motions. 



In the present case, the revolving motion of these globules appeared to be, not 

 as we are accustomed to regard the planetary motions, as the effect of a direct 

 attractive and repulsive power, in combination with a projectile force, but as revolv- 

 ing in a circulating medium, attended by an emanation from the globules them- 

 selves. 



This experiment was performed with a small vial. Perhaps a larger one would 

 render the result more perspicuous Brewster's Journal. No. V. p. 51. 



Power of metallic rods or wires to decompose water after their connection with 



the galvanic pile is broken In the experiments which I undertook in 1806-7, 



in company with Mr. Hisinger, we had found that rods of metal which were em- 

 ployed to decompose water by means of the galvanic pile continued to develope 

 gas after their connection with the pile had ceased, — a circumstance which seemed 

 to indicate a continuance of electrical state, though these rods showed no action 

 upon any other portion of liquid, even of the same kind, than that in which they 

 had been placed during their contact with the pile. This observation, which I 

 had almost forgotten, has been lately confirmed by PfafF, who has also added to 

 it several others of a similar kind. We might suppose such effects to be produced . 

 by a residual polarity, both in the liquid and the metal, showing itself, as long 

 as it continued, by a continuance of chemical action ; but some of PfafF's ex- 

 periments seem to oppose this idea, for he found that the addition of ammonia to 

 the liquid, by which all its internal polarity was destroyed, did not deprive the 

 wires of their effect. The metals which acquire this property in the highest de- 

 gree are zinc and iron, next to which is gold. He attempts to explain the phe- 

 nomenon, by supposing that the continued passage of the electrical stream had 

 brought the elements of the water nearer to a state of separation, so that a very 

 slight influence was sufficient to destroy their union. It must be confessed, how- 

 ever, that we cannot at present advance a satisfactory explanation Berzelius, 



4rsberdttelse, 1829, p. 33.— J did. 



Detection of alloy in silver by the magnetic needle Oersted has made an 



ingenious and novel application of the magnetic multiplier. He finds that if a 

 good electro-magnetic multiplier, with double needles, be suspended by a hair or 

 a thread of unspun silk between two pieces of wrought silver, differing only one 

 per cent, in the quantity of copper they contain, so sensible an effect is produced 

 upon the needle as to render this a more accurate method of proof than the com- 

 mon touch-stones. Small trial plates are made of different degrees of purity, and 

 the piece to be tried is compared with them in the following way : A thin piece 

 of woollen cloth is dipped in muriatic acid, and laid upon the trial plate, after 



