214 ANNUAL OF SCIENTIFIC DISCOVERY". 



due simply to those rays of the spectrum which are transmitted by both. 

 Instances of this both in mixtures and in chemical combinations were given. 

 From the fact of a particular ray being transmitted through a solution of 

 unknown composition, we may infer that none of those bodies which in 

 ordinary combination absorb that ray are present in any kind of combina- 

 tion. The prism also will frequently give more positive information respect- 

 ing the composition of a substance, as Avas illustrated by the fact that salts 

 of nickel, protoxide of iron, and of uranium, and some salts of chromium, 

 copper, ferric oxide, and molybdenum, besides ferrid cyanides and certain 

 compound colored salts, are all green, yet they are easily discriminated by 

 the prism. Dr. Gladstone believed that the prism might occupy a similar 

 place in our laboratories to that now occupied by the blowpipe. 



ON THE LIGHT OF SUNS, METEORS AND TEMPORARY STARS. 



The following paper, by Mr. D. Vaughan, of Cincinnati, was read before 

 the British Association at its last meeting : 



Modern science recognizes shooting stars, fire-balls, and meteoric stones, 

 as bodies which enter our atmosphere from external space with immense ve- 

 locities. From the great elevation at which these objects are luminous, it has 

 been inferred that their light has little or no dependence on aerial action ; and, 

 indeed, the presence of the air alone could not account for the greatness of 

 the illumination which marks their approach to the earth, but ceases when 

 they enter the dense stratum of the atmosphere. The diameter of many 

 luminous meteors has been estimated at two or three thousand feet ; and 

 the globe of light which they exhibited mu-st have been several million times 

 greater than the largest meteoric stone yet found on the earth's surface. It 

 is supposed that these brilliant exhibitions are produced by cosmical masses 

 several hundred yards in diameter, which, in traversing the planetary 

 regions, occasionally sweep through the verge of our atmosphere, and, after 

 casting a few fragments on the earth, continue their course through space. 

 But the idea that such wandering bodies should graze our planet so often, 

 without ever striking it directly or falling to its surface, is too extravagant 

 to be seriously entertained. It would be far more likely that, during a naval 

 engagement, a ship should be almost touched by several thousand balls, 

 without being ever struck by a single one. Moreover, there is not the slight- 

 est evidence that meteorites ever perform such remarkable feats of precision, 

 or experience so many narrow escapes from a collision with the earth, fcr, 

 instead of being observed departing into space, they suddenly disappear after 

 their encounter with the air. The small amount of solid matter which falls 

 to the ground o;i these occasions is justly regarded as inadequate to evolve 

 so vast a body of light by acting on the rarefied air at great elevations ; but 

 our globe seems to be invested with an atmosphere of ether, having far more 

 wonderful properties. Astronomical investigations prove the existence of a 

 rare medium pervading all space ; and this subtle fluid cannot be wholly in- 

 sensible to chemical forces, which alone could render it useful in nature's 



