LECTURE ON THE RESULTS 



OF 



SPECTRUM iLNALYSIS APPLIED TO THE HEAVENLY BODIES, 



DEUVERKD BEFORE THE 

 BRITISH ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. AUGUST 23, 1866. 



BY Wll. HUGGINS, F. R. S., ETC. 



An impoi'tant invention or discovery seldom, if ever, remains sterile and alone. 

 It gives birth to other discoveries. The telescope and the microsco[)e have led 

 to remarkable discoveries in a^^tronomy and in minute anatomy and physiology, 

 Avhich would not have been possible without those instruments. The observation 

 that a magnetic body, free to move, arranges itself nearly north and south, has 

 not only contributed immensely to the extension of commerce and of geographical 

 discovery, but also has founded the important science of terrestrial magnetism. 



This evening I have to bring before you some additions to our knowledge in 

 the department of astronomy, which have followed from a comparatively recent 

 discovery. The researches of Kirchhoflf have placed in the hands of the astron- 

 omer a method of analysis which is specially suitable for the examination of the 

 heavenly bodies. So unexpected and important are the results of the application 

 of spectrum analysis to the objects in the heavens that this method of obser- 

 vation may be said to have created a new and distinct branch of astronomical 

 science. 



Physical astronomy, the imperishable and ever growing monument to the 

 memory of Newton, may be described as the extension of terrestrial dynamics 

 to the heavens. It seeks to explain tlie movements of the celestial bodies on the 

 supposition of the universality of an attractive force similar to that which exists 

 upon the earth. 



The new branch of astronomical science Avhich spectrum analysis may be said 

 to have founded, has for its object to extend the laws of terrestrial physics to 

 the other phenomena of ihe heavenly bodies, and it rests upon the now estab- 

 lished fact that matter of a nature common to that of the earth, and subject to 

 laws similar to those which prevail upon the earth, exists throughout the stellar 

 universe. 



The peculiar importance of Kirchhoff 's discovery to astronomy becomes obvious 

 if we consider the position in which we stand to the heavenly bodies. Gravita- 

 tion and the laws of our being do not permit us to leave the earth; it is, therefore, 

 by means of light alone that we can obtain any knowledge of the grand array 

 of worlds which surround us in cosmical space. The star-lit heavens is the only 

 chart of the universe we have, and in it each twinkling point is the sign of an 

 immensely vast though distant region of activity. 



Hitherto the light from the heavenly bodies, even when collected by the largest 

 telescope, has conveyed to us but very meagre information, and in some cases 

 only of their form, their size, and their color. The discovery of Kirchhoff en- 

 ables us to interpret symbols and indications hidden within the light itself, which 

 furnish trustworthy information of the chemical, and also to some extent of the 

 physical, condition of the excessively remote bodies frpm which the light baa 

 emanated. 



