858 M. Latour''s Observations on the Cause and 



their prize : What are the distivguishing Characters in Vege- 

 table and Animal Matters which excite^ and those which undergo, 

 the process of Fermentation? This question, which was again 

 proposed in the year 1802, was withdrawn in the year 1804, as 

 well as those proposed by the other classes, on account of an 

 unexpected event which deprived the Institute of the funds 

 which were intended to pay the prizes. 



This great question concerning the unknown action of the in- 

 ternal movement of fermentation, and its extraordinary results, 

 a question which, at one and the same time, relates to physics, 

 chemistry, and physiology, having remained so long unsolved, 

 M. Cagniard Latour, who has been engaged with it for more 



sphere may increase and not decrease with the height, even previous to 

 liie setting of the sun. Certain arrangements, which for a long while I have 

 contemplated, would enable me to subject this conjecture to a decisive 

 proof. In the mean while, we would suggest that the Academy should soli- 

 cit the members of the Northern Expedition to prosecute with continued 

 attention the phenomenon which I have submitted to their notice. A ba- 

 loon with a cord attached to it, which would convey a self-registering ther- 

 mometer, and which might be made to ascend from time to time, would 

 furnish more conclusive observations than any that could be made on a 

 mountain, however isolated or steep. The only recommendation we would 

 make would be, to substitute a horizontal thermometer, for those of Ruther- 

 ford and Six with a moving index, whose employment can be little de- 

 pended upon, on account of the violent oscillations of the baloon during the 

 ascent and descent, and even during its somewhat protracted sojovirn at its 

 highest elevation. * 



• After this paragraph was written, I found in the work of M. Pictet some ob- 

 servations upon atmospheric temperatures increasing with the elevation, which 

 were made during the night, or at least when the sun was below the horizon. 

 M. Biot has also sent me the following note, regarding the obserj^ations of 

 General Roy and Dr Lind, upon the measurement of heights by the barometer, 

 taken from the Phil. Trans. 1777, p. 728. After citing some observations taken 

 at very insignificant elevations, in which, by local influences, the upper thermo- 

 meter had indicated a somewhat higher temperature than the lower, the author 

 adds, " But the most remarkable example of this kind occurred in one of Dr 

 Lind's observations, when a thaw supervened, on the 31st Jan. 1776, to a'severe 

 frost. At Hawk Hill near Edinburgh (the lower station) at lOh. 45' a.m., the 

 temperature in the open air was 14° Fahr. ; when at the top of Arthur Seat (the 

 higher station) it was at 20° F. The ground, which «till continued frozen, kept 

 the air very cold below, whilst the thaw had made considerable progress on the 

 top of the hill — The difference of the level of the stations here specified was 

 684 English feet, and the excess of the temperature at the top of the column 

 was 6° ; but as the intermediate elevations were not examined, it cannot be de- 

 termined whether this increase was continuous, or if a real decrease had not pre- 

 viously existed at the higher station. 



