4o6 POPULAR SCIENCE MONTHLY. 



address in Latin, so tliat every one could understand it. Slie re- 

 garded him attentively, and they then began to converse in the same 

 language on the origin of fountains and the cause of the flow and 

 ebb, like that of the sea, which some springs exhibit. She spoke 

 like a superior intelligence on the subject; I have heard nothing 

 upon it that gave me more satisfaction. After this conversation. 

 Count Belloni invited me to talk with her in the same way on any 

 subject I pleased, in philosophy or mathematics. I was astonished to 

 find that I was expected to speak impi^omptu and in a language to 

 which I was little used; but, be it as it might, I paid her a hand- 

 some compliment, and then we discoursed concerning the way in 

 which mind could be affected by corporeal objects and communi- 

 cate concerning them with the organs of the brain; and afterward 

 concerning the emanation of light and the primitive colors. Toppin 

 conversed with her on the transparency of bodies and on the prop- 

 erties of certain geometric curves, of which I understood nothing. 

 Evidently Agnesi's parties are hardly of this world ! " 



When Agnesi was nineteen years old, she had already sustained 

 one hundred and ninety-one philosophical theses.* Of course, they 

 are somewhat superficial theses, in which, after having cited the 

 principal views of various authors, Agnesi discussed and affirmed her 

 own opinion. This proves, nevertheless, that she had received a some- 

 what more solid instruction than was till recently given to the young 

 women of our time. The inquiring quality of her mind and her 

 taste for science are likewise revealed in her correspondence. On 

 April 26, 1733, she received from Father Manara a letter from Rome 

 which resolved some of her doubts concerning ballistics. In another 

 letter she sent Count Charles Belloni the solution of a problem in 

 analytical geometry; and a response from him (July 5, 1735) cleared 

 up some difficulties which she had met in reading the Conic Sec- 

 tions of the Marquis de I'Hopital, published in 1707, of which she 

 had undertaken to make a commentary. 



'Not these labors alone engaged her thoughts. Toward her 

 twentieth year, in the very midst of her success, she contemplated 

 retiring from the world to enter a religious society, now suppressed, 

 called the Celeste, or Turquine, from the color of their dress, or 

 Carcanine, from the name of their founder, Giovanni Pietro Car- 

 cano. But, in view of the distress that this resolution cost her father, 



* They have been published under the title Propositiones philosophicae quas crebris 

 disputationibus domi habitis coram clarissimis viris explicabet ex tempore et ab objectis 

 vindicabat Maria Cajetana de Agnesis Mediolanensis (Philosophical propositions which 

 Maria Gaetana Agnesi, of Milan, explained ex tempore and vindicated from objections in 

 frequent disputations held at home in the presence of the most distinguished men), Medio- 

 lani (1738), and they are dedicated to Charles Belloni, of Paris. 



