Condensation of Humidity on Solid Surfaces. 251 
enabled quickly to dissolve the thin crust of ice, even though 
its temperature did not nearly equal that of the originally in- 
closed air. For, air having a temperature of 27°, when sud- 
denly raised 9° or 10° (and it might in this case have risen con- 
siderably higher) would be in a state well fitted to dissolve a 
thin crust of ice. The front windows were warmer, and there- 
fore free of ice, from being shaded by the cabriolet, which 
would itself be somewhat heated by its inmates, and would pre- 
vent the external cold air from directly impinging on the glass. 
It might also have happened, that the stream of heated air pro- 
ceeding from the bodies of the drivers and horses, had some in- 
fluence, and which would necessarily be most effective on the 
front parts of the coach. 
There are a variety of interesting facts and appearances in 
nature connected with the subject of this paper, which remain 
to be considered. In accounting for these, the principle of ra- 
diation has also been supposed to be applicable, if not essential. 
It would seem, however, that they admit of explanation, by ta- 
king a more simple, and therefore, possibly, more just view of 
the subject. The operations of nature often appear complex, but, 
when best understood, are found to be extremely simple. How 
effectually does this acknowledged simplicity and apparent intri- 
cacy often conceal from us the truth ? Leading us into some by- 
path, where a mental phantasmagoria'springing up, first pleases, 
then interests, and ultimately so deceives and blinds, that no- 
thing is believed to possess so much of reality as that which a 
few passing years, at most, discloses as the veriest £< fabric of a 
vision.” 
Explanation of the Figures , Plate IX. 
The aspects of the windows are marked above the Figures, and 
under them the existing temperatures of the internal and external 
air, that of the latter being the lowest. 
Fig. 1. Observed at Paris. The house was situated on what is con- 
sidered the highest ground within the gates ; the beiveder 
commanding a panoramic view of the whole city. Nothing 
interrupted the view from the window to the most distant ho- 
rizon. 
