MOVEMENTS OF JUPITER'S CLOUD-MASSES. 8 



TABLE B. 



Upper pole, gold 



Lower " copper 



Upper " gold and copper 



Lower " copper 



Upper " silver 



Lower " tiu 



Upper " nickel 



Lower " " 



3s Ul) I) 



1 y 4 u u u 



y 7 t) ii(ju 

 9" 7 6 CiJjT) 



3"8!illU" U 

 T?4U0TT0 



While it is probable that (with the exception, perhaps, of Fara- 

 day's researches) we have not here indicated the smallest particles of 

 metal which it would be possible to determine by the delicate means 

 at our disposal, it is thought that the experiments recorded may prove 

 interesting, as showing what has been, and what may be, accomplished 

 in this direction ; and, lest any incredulous reader should fancy that, 

 when we speak of weighing the three million eight hundred and 

 eighty-thousandth part of a grain of metal, we are toying with imagi- 

 nary fractions, we would refer him to Sir William Thomson's esti- 

 mate of the size of the final molecules ; ' compared with which this 

 unit is as large as the famous Philadelphia cobble-stones compared 

 with grains of sand upon the sea-shore. In conclusion, we are led to 

 appreciate the wisdom as well as the wit of the distich 



" E'en little fleas have lesser fleas upon their backs to bite 'em ; 

 And these again have lesser fleas, and so ad infinilum.'''' 



MOVEMENTS OF JUPITEE'S CLOUD-MASSES. 



By RICHARD A. PROCTOR. 



IF Jupiter be regarded as a planet resembling our earth in condition, 

 we find ourselves compelled to believe that processes of a most 

 remarkable character are taking place on that remote world. It is 

 singular with what complacency the believers in the theory that all 

 the planets are very much alike accept the most startling evidence 

 respecting disturbances to which some among those brother worlds 

 of ours must needs on that hypothesis have been subjected. Mighty 

 masses of cloud, such as would suffice to enwrap the entire globe on 

 which we live, form over large regions of Jupiter or Saturn, change 

 rapidly in shape, and vanish, in the course of a few minutes ; and 

 many are content to believe that what has thus taken place resem- 

 bles the formation, motion, and dissipation, of our own small clouds, 



' He fixes the limit between the gsooooooo and the TtrowinTTrfrTf of an inch, and says 

 that they are " pieces of matter of measurable dimensions, with shape, motion, and laws 

 of action ; intelligible subjects of scientific investigation." 



VOL. XI. 6 



