lvi REPORT — 1865. 



The proportion of carbonic acid gas in the atmosphere at great heights is 

 not yet ascertained : it is not likely to be the same as that generally found 

 near the earth ; but its proportion may be more constant, since in those 

 regions it is exempt from the influence of the actions and reactions which 

 are always in progress on the land and in the water, and do not necessarily 

 compensate one another at every place and at every moment. 



Other information bearing on the constitution of the atmosphere comes to 

 us from the auroral beams and other meteoric lights known as shooting-stars. 

 For some of these objects not only appear at heights of ten, fifty, and one 

 hundred or more miles above the earth, but at the height of fifty miles it is 

 on record that shooting-stars or fire-balls have left waving trains of light, 

 whose changes of form were in seeming accordance to varying pressure in the 

 elevated and attenuated atmosphere *. 



Researches of every kind have so enriched meteorology since our early 

 friend, Professor J. Forbes, printed his suggestive reports on that subject, and 

 so great have been the benefits conferred on it by the electric telegraph, that 

 at this moment in M. Leverrier's observatory at Paris, and the office so lately 

 presided over by Admiral FitzEoy in London, the messages are arriving from 

 all parts of Europe to declare the present weather, and furnish grounds for 

 reasonable expectation of the next probable change. Hardly now within 

 the seas of Europe can a cyclone begin its career of devastation, before the 

 warning signal is raised in our sea-ports, to restrain the too confident sailor. 

 The gentle spirit which employed this knowledge in the cause of humanity 

 has passed away, leaving an example of unselfish devotion, in a work which 

 must not fail through any lack of energy on the part of this Association, the 

 Royal Society, or the Government. We must extend these researches and 

 enlarge these benefits by the aid of the telegraph bringing the ends of the 

 world together. Soon may that thread of communication unite the two great 

 sections of the Anglo-Saxon race, and bring and return through the broad 

 Atlantic the happy and mutual congratulations for peace restored and friend- 

 ships renewed. 



The possible combinations of force by which, in the view we have been 

 considering, the characteristic forms and special phenomena of solid, liquid, 

 and gaseous matter are determined, may be innumerable. Practically, how- 

 ever, they appear to be limited, as natural products, to less than one thousand 

 distinguishable compounds, and less than one hundred f elementary sub- 

 stances. Of these elements the most prevalent are few on the earth ; as of 

 gases, oxygen, hydrogen, nitrogen ; of solids, silicon, calcium, magnesium, 

 sodium, iron ; and it is interesting to learn by analysis of the light of stars 

 and planets, that these substances, or some of them, are found in most of the 

 celestial objects yet examined, and that, except in one or two instances, no 

 other substances have been traced therein. Even the wandering meteoric 

 stones, which fall from their courses, and are examined on the earth, betray 

 only well-known mineral elements, though in the manner in which these are 

 combined, some differences appear, which by chemical research and the aid 

 of transparent sections Professor Maskelyne and Mr. Sorby are engaged in 

 studying and interpreting +. 



* This is the result of a careful discussion made by myself of observations on a meteor 

 seen from Rouen to Yorkshire, and from Cornwall to Kent, Jan. 7, 1856. 



f At the present moment the number of " elementary substances " is sixty-one. 



f Professor Maskelyne has made a convenient classification of the large collection of 

 meteorites in the British Museum, under the titles of "Aerolite or Meteoric Stone;" 

 * Aerosiderite or Meteoric Iron ;" and " Aerosiderohtes," which includes the intervening 



