34 PRESIDENTIAL ADDRESS SECTIOX A. 



I do not w isli to discurS'S here if ill at iden may some day come 

 true. Animated life is a mere and short incident in the evolution 

 of a celestial body; and of the livintr beings there may be as great 

 a. variety as on the earth, where the simple bacteria are as real 

 inhabitants as men arc. I mention this case only because it 

 seems to me that it is the one which has attracted the attention 

 of the people to astronomy^ 



The other wish of mankind, the predicting of the future, also 

 in a certain manner was flattered by astronomy. I do not refer 

 to the superstition of the olden days, which even now is not 

 thoroughly dissolved, of the influence of the planets upon our 

 lives. I only refer to the accuracy with which the methods of 

 astronomy allow us to know, centuries in advance, the positions 

 of celestial bodies. It M'as always a case which pleased the 

 people, the knowing that on such a day and at such an hour there 

 would be an eclipse of the sun in this or other circumstances. 



It is thanks to this prestige that astronomy has been able 

 to progress and thanks to its progress that the other sciences 

 have been able to advance. 



In three different ways has astronomy helped the other 

 sciences : firstty , giving them the certainty that Nature is 

 ruled by laws; that in the world reign Harmony and simplicity; 

 secondly, giving them the models and putting successive 

 problems; and, thirdly, assisting them with the help of 

 observations. 



The contemporaries of Tycho Brahe might have asked what 

 utility his extended observations could have. Perhaps Tycho 

 himself did not recognise in them a utility other than that of 

 delighting his mind. But we know that those observations 

 allowed Kepler to enunciate his well-known laws; and these 

 laws revealed to mankind, that in the apparently arbitrary and 

 complicated motions of the j^lanets, there is something of the 

 common and simple. 



From the laws of Kepler, Newton deduced his celebrated law 

 of gravitation, which can be considered as a vesuyne or condensa- 

 tion of them. But the field of its application was extended. 

 The motion of the comets, which Kepler despised, because he 

 believed they were simple meteors, showed that they obeyed the 

 same law. The moon and the bodies with which we deal here, 

 at the earth's surface, all obey Newton's law. Later on, it was 

 ascertained that the components of double stars also obey this 

 law. 



The influence of Newton's law upon the human mind was 

 enormous, and this influence was exerted in three ways. Firstly, 

 a law that prevails through all known space revealed to mankind 

 that Nature is everywhere the same, disciplined and simple in 

 its elementary processes. There was found in Nature an 

 unexpected harmonj- which gave man the courage to enter 

 deliberately on the search for the secrets of Nature, because he 

 Icnew from that time such secrets were not impenetrable. 



