332 On the Quantify of Carbonic Acid Gas [Nor, 



carbonic acid emitted from the lungs in the morning about the 

 commencement of twilight. This circumstance appeared so inte- 

 resting, that I determined to ascertain, if possible, whether it were 

 merely accidental, or whether it really obeyed the movements of 

 the sun. With this view, therefore, I commenced a series of 

 experiments about the winter solstice; which was continued, at 

 intervals, nearly till the summer solstice ; a period which, of course, 

 included all the variations in the sun's rising. These experiments 

 were made by staying up the whole of the night, and repeating the 

 operations occasionally during that time, with the same instrument, 

 and precisely in the same manner, as formerly described. The 

 following are the details : — 



TABLE I. 



April 3, 18 14. 

 Bar. 29-6. Ther. 50. 



v. M 



If> 

 II 



12 

 1 



2 

 3 



4 



15 

 8 



Cub? In. 

 Carb. Acid. 



. 330 

 . 330 

 . 330 

 . 3 30 

 . 330 

 . 335 

 . 3-60 



May 12, 1814. 

 Bar. 30-2. Ther. 50. 



P Mi 



9" 10' 



10 — 



11 — 



12 — 

 1 — 

 2 



20 



Cub. In. 

 Carb. Acid. 



. 3-70 

 . 3-60 

 . 3-00 

 . 330 

 . 330 

 . 350 



Aug. 21, 1813. 



Bar. 29-8. Ther. 62. 



p.m. 

 9" 30' 



10 



11 



12 



1 



2 



30 

 30 

 30 

 20 



45 



Cub. In. 

 Carb. And. 



.. 3-50 

 . . 3-50 

 .. 3-60 

 .. 350 

 .. 3-65 

 .. 3-90 



TABLE II. 



* The heights of the barometer are taken from meteorological tables kept in 

 and near London, and heme are to be considered only as approximations. 



+ 1 grew very sleepy at this time. Will thin account for (he diminution ? 



j These are < nly to be considered as approximations. They were taken from a 

 common almanack ; and are sufficiently accurate for our present purpose. 



