S42 



COJfGELAtlON. 



action perpen- 

 dicularly 

 downward. 



itself J a ring »J?lee will be found adhering to the circum- 

 ference of the plate in the morning ; but the water im- 

 mediately under Tsip £tinnel will retain its fluidity. 

 Experiment to The perusat of M. Dispan's ingenious essay brought 



determine gevcral facts to my recollection, which rendered the accu- 

 whethertlie '' ; , ,. , , 



freezing is ef- racy of the preceding narrative somewhat disputable ; 



fectcd by an ^ut memory too frequently preserves the outlines of 

 events, while she neglects to record collateral circum- 

 stances of importance ; I therefore resolved to try the 

 merits of the Parisian's relation by experiment the first 

 opportunity. This design was soon accomplished; for a 

 suitable occasiou presented itself on the 21st of Novem- 

 ber. The evening was perfectly calm ; and I found the 

 copper funnel of a rain gauge slightly incrusted with hoar 

 frost at 7 P. M. A saucer, containing water, was imme- 

 diately placed upon a stand in the middle of a garden, 

 one half of this vessel being covered with a pane of glass, 

 while the other remained exposed, and the distance of | 

 of an inch separated the glass from the water. The 

 evening proved very favourable to the experiment, for 

 hoar frost fell copiously upon slender bodies, such as 

 gates and pales, as the night advanced, but the gravel 

 Walks of the garden remained wet at 11 P.M. The 

 saucer was visited at this time, when it was found per- 

 fectly covered with a film of ice, and both sides of the 

 glass were incrusted with rime. The film on the saucer 

 grew thicker in the course of the night; but the vessel of 

 water which stood upon the sole of a window in the gar- 

 den remained unfrozen in the morning. 



Were the preceding remarks submitted to the consider- 

 ation of M. Dispan's friend, perhaps he would say, that 

 the lintel «f the window protected the vessel standing 

 dwelling house ^jjjI^p I (- from the frigorific particles, by interrupting 

 impede* frecz- . . a- i a ^ \i ^i. . 



ingontKe their perpendicular descent; consequently the water rc- 



groundnear it. twined its fluidity, being sheltered from the influx of thoss 

 minute bodies which constitute the true cause of congela- 

 tion. The experiment might also be rejected by the same 

 philosopher not without someshe>v of reason, for it evi- 

 dently answered his expectations in one instance, though 

 it disappointed them in another. The same objections 

 may be urged, with equal effect, by those who suppose 



that 



It dtd not 

 prove so. 



The facts indi 

 care that the 

 swpeiior tem- 

 perature of a 



