DISCOVEHIES IN THE C1L1LESTIAL SPACES. 721 



The invention of instruments for measuring temperature 

 (Galileo's thermoscopcs of 1593 and 1602,* depending 

 simultaneously on the changes in the temperature and the 

 external pressure of the atmosphere,) gave origin to the idea 

 of determining the modifications of the atmosphere by a 

 series of connected and successive observations. We learn 

 from the Diario ddl Academia del Cimento, which exercised 

 so happy an influence on the taste for experiments conducted 

 in a regular and systematic method during the brief term of 

 its activity, that observations of the temperature were made 

 with spirit-thermometers similar to our own at a great num- 

 ber of stations, amongst others at Florence, in the convent 

 Degli Angeli, in the plains of Lombardy, on the mountains near 

 Pistoja, and even in the elevated plain of Innspruck, as early 

 as 1641, and five times daily. f The Grand Duke Ferdinand 

 II. employed the monks in many of the monasteries of his 

 states to perform this task.J The temperature of mineral 

 springs was also determined at that period, and thus gave 

 occasion to many questions regarding the temperature of the 

 earth. As all natural phenomena all the changes to which 

 terrestrial matter is subject are connected with modifications 

 of heat, light, and electricity, whether at rest or moving in 

 currents, and as likewise the phenomena of temperature acting 

 by the force of expansion, are most easily discernible by the 

 sensuous perceptions ; the invention and improvement of 

 thermometers must necessarily, as I have already elsewhere 

 observed, indicate a great epoch in the general progress of 

 natural science. The range of the applicability of the tlier- 



* On the oldest thermometers, see Nelli, Vita e commercio let- 

 terario di Galilei (Losanna, 1793), vol. i. pp. 88-94; Operedi Galilei 

 (Padovo, 1744), t. i. p. Iv. ; Libri, Histoire des Sciences mathematiques 

 en Italic, t. iv. (1841,) pp. 185 197. As evidences of first comparative 

 observations on temperature, we may instance the letters of Gianfrancesco 

 Sagredo, and Benedetto Castelli in 1613, 1615, and 1633, given in 

 Venturi, Memorle e Lettere inedite di Galilei, P. i. 1818, p. 20. 



+ Vinccnzio Antinori, in the Saggi di Naturali Esperienze, fatte 

 nell 1 Accademia del Cimento, 1841, pp. 30 44. 



% On the determination of the thermometric scale of the Accademia 

 del Cimento, and on the meteorological observations continued for six- 

 teen years by a pupil of Galileo, Father Raineri, see Libri, in the 

 Annales de Chimie et de Physique, T. xlv. 1830, p. 354; and a more 

 recent similar work by Schouw, in his Tableau du Climat ct de la 

 Vegetation de I'ltalie, 1839, pp. 99106. 



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