# Page:Popular Science Monthly Volume 3.djvu/462

448
THE POPULAR SCIENCE MONTHLY.

 Walking in the sea is 1.65 ⁠"⁠on land at 1 mile per hour " 1.9 Riding on horseback at the walking pace " 2.2 Walking at 2 miles per hour " 2.76 Riding on horseback at the cantering pace " 3.16 Walking at 3 miles per hour " 3.22 Riding moderately " 3.33 Descending steps at 640 yards perpendicular per hour " 3.43 Walking at 3 miles per hour and carrying 34 lbs. " 3.5 ⁠"⁠"⁠"⁠62 lbs " 3.84 Riding on horseback at the trotting pace " 4.05 Swimming at good speed " 4.33 Ascending steps at 640 yards perpendicular per hour " 4.4 Walking at 3 miles per hour and carrying 118 lbs " 4.75 ⁠"⁠4 miles per hour " 5 The tread-wheel, ascending 45 steps per minute " 5.5 Running at 6 miles per hour " 7

Another table, from the same series of experiments, illustrates the same effect on the basis of the amount of carbonic acid evolved by respiration per minute:

No. 7.
 In profound sleep, lying posture 4.5 grains In light sleep, lying posture 4.99 " Scarcely awake, 1½ a. m. 5.7 " ⁠"⁠"⁠2½ a. m. 5.94 " ⁠"⁠"⁠6¼ a. m. 6.1 " Walking at 2 miles per hour 18.1 " ⁠"⁠3 miles per hour 25.83 " Tread-wheel, ascending 28.15 feet per minute 43.36 "

Thus it is possible that the amount of vital change proceeding in the body may be ten times greater in one state than in another, and it follows that a proportionate quantity of food will be required to sustain it.

 LUNAR TEMPERATURES.

POETS have so long sung of the cold, chaste Moon, pallid with weariness of her long watch upon the Earth (according to the image used alike by Wordsworth and Shelley), that it seems strange to learn from science that the full moon is so intensely hot that no creature known to us could long endure contact with her heated surface. Such is the latest news which science has brought us respecting our satellite. The news is not altogether unexpected; in fact, reasoning had shown, long before the fact had been demonstrated, that it must be so. The astronomer knows that the surface of the moon is exposed during the long lunar day, lasting a fortnight of our terrestrial time, to the rays of a sun as powerful as that which gives us our daily heat.