440 Royal Society : — 



determined by several sets of experiments. Four of these, consisting 

 of eight experiments, were made upon four gentlemen, on the author, 

 Professor Frankland, F.R.S., Dr. Murie, and Mr. Moul, during the 

 eighteen hours of the working day. In two of them, the whole of 

 the carbonic acid was collected, and in two others the experiment 

 was made during ten minutes at the commencement of each hour, 

 and of each hour after the meals. The quantity of carbonic acid 

 varied from an average of 24'274 oz. in the author to 1()'43 oz, in 

 Professor Frankland. The quantity evolved in light sleep was 4-88 

 and 4-99 grahis per minute, and when scarcely awake 5-7, 5*94, and 

 6-1 grains at different times of the night. The author estimates the 

 amount in profound sleep at 4-5 grains per minute ; and the whole 

 evolved in the six hours of the night at 1950 grains. Hence the total 

 quantity of carbon evolved in the twenty-four hours, at rest, was, in 

 the author, 7-144 oz. The effect of walking at various speeds is then 

 given, with an estimate of the amount of exertion made by different 

 classes of the community, and of the carbon which would be evolved 

 with that exertion. 



The author then states the quantity of air inspired in the working 

 day, which varied from 583 cub. in. per minute in himself to 365 

 cub. in. per minute in Professor Frankland ; the rate of respiration, 

 which varied in different seasons as well as in different persons ; the 

 depth of inspiration, from 30 cub. in. to 39"5 cub. in. ; and the rate of 

 pulsation. The respirations were to the pulsations as 1 to 4-G3 in 

 the youngest, and as 1 to 5-72 in the oldest. One-half the product 

 of the respirations into the pvdsations gave nearly the number of 

 cubic inches of air inspired in some of the persons, and the propor- 

 tion of the carbonic acid to the air inspired varied from as 1 gr. to 

 54*7 cub. in. to as 1 gr. to 58 cub. in. The variations in the carbonic 

 acid evolved in the working day gave an average maximum of 10 "4 3, 

 and minimum of 6-74 grains per minute. The quantity increased 

 after a meal and decreased from each meal, so that the minima were 

 nearly the same, and the maxima were the greatest after breakfast 

 and tea. 



The effect of a fast of forty hours, with only a breakfast meal, was 

 to reduce the amount of carbonic acid to 75 per cent, of that which 

 was found with food ; to render the quantity nearly uniform through- 

 out the day, with a little increase at the hours when food had usually 

 been taken, and to cause the secretions to become alkaline*. 



The variations from day to day were shown to be connected with 

 the relation of waste and supply on the previous day and night, so 

 that with good health, good night's rest, and sufficient food, the 

 amount of respiration was considerable on the following morning, 

 whilst the reverse occurred with the contrary conditions. Hence 

 the quantities were usually large on the Monday. Temperature was 

 an ever-acting cause of variation, and caused a diminution in the 

 carbonic acid as the temperature rose. 



* The quantity of air was reduced 30 per cent., that of vapour in the expired air 

 50 per cent.', the rate of respiration was reduced 7 per cent., and of pulsation 6 

 per cent. 



