196 SECTION PHYSICS. 



instruments, there was chosen from among them a small number, that 

 would give an adequate idea of the History of Science in Italy, and 

 especially in Tuscany. 



Two instruments, however, although not Italian ones, were chosen 

 as a mark of homage to your noble country : the one was the invention 

 of a countryman of yours ; the other was made use of, in many cele- 

 brated experiments, by another Englishman. In the Times of the 

 2oth of this month, there is this statement : " Besides this, there are 

 other astrolabes of different countries French, German, Arabic, 

 and Persian, but unfortunately no English specimen." Now you 

 have before you here the astrolabe of Lord Dudley, and in return for 

 having placed before his eyes an English astrolabe, I would ask the 

 Times' reporter to be good enough to notice, also, the Italian astrolabes, 

 which are exhibited in our cases. 



But not only these astrolabes, but these astronomical quadrants, 

 these sundials, this series of instruments, in a word, will be able to 

 give an idea of the manner in which, during the i6th and I7th 

 centuries, mathematical and astronomical science was cultivated in 

 Italy ; and how numerous and renowned were the artificers of such 

 apparatus. 



Here is the great lens, made by Benedetto Bregans, of Dresden, and 

 presented by him, about the year 1690, to the Grand Duke Cosimo III. 

 About the beginning of this century it was made use of by your 

 celebrated philosopher, Sir Humphry Davy, in the researches which 

 he made in Florence, together with Faraday, who was at that time his 

 assistant, on the chemical constitution of the diamond. 



I must, however, tell you that Averani and Targioni had already 

 succeeded, by means of the aforesaid lens, in vaporizing the diamond. 

 We now come to the barometrograph of Felice Fontana, a well-known 

 scientific man, born in Rovereto, and who was Director of the Royal 

 Physical and Natural History Museum of Florence, founded by Peter 

 Leopoldo. Not to impose upon the indulgence which you have so 

 kindly granted me, I will omit describing to you the other experiments 

 made by Fontana, who, in order to push forward meteorological 

 science, constructed, upon the principle which you see here before you, 

 a barometrograph, a thermometrograph, and other self-registering 

 instruments. You will be able by the help of photography to under- 



