386 Intelligence and Miscellaneous Articles. 



Amphibia. — In the geometric tortoise ; in the common lizard, lead 

 being also present in greater quantity than that of the copper ; in 

 that of the common adder ; and in the brown frog. 



Fishes. — In the eel and in the haddock, the former containing the 

 largest quantity. 



Crustacea. — In the common shrimp, copper was found in abun- 

 dance. A Scolopendra italica left 1*52 gr. of ash, containing *OI5 gr. 

 of copper. 



Insects. — 231*4 grs. of Spanish flies left 12'65 grs. of ash, contain- 

 ing '0092 gr. of copper. 



Arachnida. — Copper was found in the ash of two South American 

 bird-catching spiders. 



Annulata. — 1157 grs. of fresh earthworm gave 163'5 gr. of ash 

 (with a considerable quantity of earth), containing *003 gr. of 

 copper. 



Among the Echinodermata, copper was detected in two small star- 

 fishes {Asterias rubens); among the Entozoa, in two round worms ; 

 among the Polypi, in a sea-anemone (Tealia crassicornis) , and in a 

 sponge. 



Copper was thus found in animals whenever it was searched for. 

 As animals live in part directly and in part indirectly upon plants, 

 it follows that it must occur in all plants ; and as plants derive their 

 contents from the soil or from sea-water, copper must be generally 

 diffused through both of these media. John and Meissner proved 

 the existence of copper in the ashes of plants more than fifty years 

 ago, while Sarzeau detected it in more than two hundred plants, and 

 searched in vain for plants free from it. This result has been more 

 recently confirmed and extended by Commaille. Copper has been 

 repeatedly detected in soils, while Durocher and Malaguti, as also 

 Field and Piesse, have found it in sea-water. 



SPECULATIONS UPON A POSSIBLE METHOD OF DETERMINING THE 

 DISTANCE OE CERTAIN VARIABLY COLOURED STARS. BY 

 JOSEPH WHARTON. 



Arago conceived the idea of testing the correctness of the corpus- 

 cular or emission theory of light by subjecting two rays of different 

 velocities to the same refracting influence; for, as that theory ex- 

 plained the refraction to be due to retardation of velocity caused by 

 the molecular attraction of the refracting medium, rays entering the 

 medium at different velocities should be differently refracted. To 

 get rays of different velocities, he took light from a star toward which 

 the earth in its orbit was moving, and from another star which the 

 earth was moving away from. Supposing the ray to strike the 

 earth from the first of these stars at the real velocity of light plus 

 the velocity of the earth, and that from the other at the real velocity 

 of light minus that of the earth, Arago had two rays entering his 

 refractor at velocities differing by about 5 ^ . Arago found no 

 difference in the refraction of his two rays, and his conclusion thence 

 derived that the corpuscular theory of light is untenable, has been 



