Page:Popular Science Monthly Volume 11.djvu/91

This page has been validated.
81
MOVEMENTS OF JUPITER'S CLOUD-MASSES.
TABLE B.
1. 2. 3. 4. 5.
Upper pole gold 20.5 20 .5 1/6000 1/388000
Lower " copper 10 9.9 .1 1/30000 1/1940000
Upper " gold and copper 21 20.4 .6 1/5000 1/324000
Lower " copper 20.2 20 .2 1/15000 1/976000
Upper " silver 6 5.8 .2 1/15000 1/976000
Lower " tin 20 19.4 .6 1/5000 1/324000
Upper " nickel 12 11.95 .05 1/60000 1/3880000
Lower "    " 12 11.9 .1 1/30000 1/1940000

While it is probable that (with the exception, perhaps, of Faraday'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 imaginary fractions, we would refer him to Sir William Thomson's estimate of the size of the final molecules;[1] 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 infinitum."

MOVEMENTS OF JUPITER'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 resembles the formation, motion, and dissipation, of our own small clouds,

  1. He fixes the limit between the 1/250000000 and the 1/6000000000 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."