1830.] The Progress of Physical Discovery. 273 



together, the one appears blue, and the other yellow. And the same 

 object lighted by either, or both at once, remains white. The light of 

 a candle, so bright when it dissipates darkness, appears yellow at mid- 

 day ; and, although moon-light gives to the night the sensation of white- 

 ness, yet, if we project upon a white body, a shade occasioned by the 

 interruption oPthe light of a candle which illumines the other parts of it, 

 the part only lighted by the rays of the moon appears of a greenish 

 blue facts which, prima facie, confirm M. Prevost's doctrine, though 

 we are not aware whether it is yet generally received. A German 

 chemist, M. Osaun, has obtained also much celebrity by his preparation 

 of three phosphorescent substances, viz. phosphorus of antimony of 

 realgar, and of arsenic, which powerfully absorb light. He has likewise 

 ascertained, that cold favours the absorption of light, as heat favours the 

 dispersion of it. Boiling water, it seems, destroys phosphorescence, and 

 phosphoric bodies, left in darkness after their preparation, are not 

 luminous, whilst they shine for a considerable time if exposed to the light 

 of the sun. 



We are here compelled to stop in our very abridged notice of a few 

 among the many discoveries recently made in physics, which, if they 

 were detailed at length in the whole, " the world itself would scarcely 

 contain the books that might be written." The progress in the other 

 branches of natural history has been equally rapid ; in fact, in these 

 sciences the advance of one furnishes a safe index to that of the rest, 

 and it is more on that account that we have selected the physical branch, 

 than by reason of any peculiar pre-eminence it has attained over others. 

 Its pre-eminence, indeed, is that of its present over its former condition 

 of its state at the end of the last century, compared to what it was a 

 century before ; and, at the present moment, in comparison with what it 

 was not thirty years since. If the last twenty years of the eighteenth 

 century were the aera of glory to Lavoisier and his distinguished school, 

 the succeeding years have produced a race of giants, whose knowledge 

 and power over nature have been absolutely unexampled. The vulgar 

 are now familiar with what, thirty years ago, were mysteries to the 

 learned ; and we cannot but be as clearly convinced of the vast distance 

 between the chemistry of the revolution and of the present day, as we 

 were whilst the illustrious Davy yet lived, that a greater than Lavoisier 

 was here. 



Besides the prodigious increase of periodical and other works, 

 throughout Europe, upon natural philosophy, we hail the institution of 

 the society of Naturalists and Philosophers, which meets annually in 

 one of the principal towns in Germany, as an important sign of the 

 times. The divided state of Germany makes such meetings particularly 

 useful there, on account of the want of a capital as the centre of com- 

 munication ; but we find, from the Reports of the Assemblies, held at 

 Berlin in September 1828, and at Heidelberg in September 1829, that 

 they were attended by delegates, not only from all parts of Germany, but 

 from Norway, Sweden, and Denmark, Russia, Poland, England, France, 

 and the Netherlands, amounting, on each occasion, to about 500. The in- 

 stitution is consequently become European ; and it may easily be conceived 

 how particularly advantageous must be the union of scientific men in an 

 annual congress, which enables them to communicate personally, and adds 

 so much to their zeal in the common cause during the ensuing year. 



M. M. New Smew. VOL. IX. No. 51. 2 N 



