The readings of temperature in the preceding Tables were formed in small groups, including observations which had been taken in quick succession, or at about the same distance from the earth, or when the balloon had passed upwards and downwards through the same space within a few minutes; as, for example, on May 29, between 6h 17m and 6h 22m These mean values at the mean height were laid down on a diagram; all these points were joined, and a curved line was drawn through, or near them, so that the areas of the space between the original and the adopted lines on one side were equal to those of the spaces on the other side. The curve thus formed was assumed to be the curve of temperature freed from local disturbance, and that it was assumed that the deviations of the original curve indicated the places and the amount of disturbance. The next step was reading from these curves the temperature at every 100 feet, and in this way the next Tables were formed. The numbers in the first column show the height in feet, beginning from the ground and increasing upwards; the numbers in the second column show the interval of time in ascending to the highest point; the notes in the third column show the circumstances of the observations; the numbers in the fourth and fifth columns, the observations and the approximate true temperatures of the air, and those in the next column the difference between the two preceding columns, or the most probable effect of local disturbing causes. The next group of columns are arranged similarly for the descent, and the other groups, on May 29, for the second ascent and second descent. TABLE III.-Showing the Temperature of the Air, as read off the curve drawn through the observed temperatures, and as read off the curve of most probable normal temperatures, called adopted temperatures, and the calculated amount of disturbance from the assumed law of decrease of temperature. The temperature of the air was the lowest on the ground, and increased, with elevation, to the height of 2000 feet, the highest point attained; and on the descent it decreased with decrease of elevation, and was the lowest on reaching the ground. 57'3 57'3 57'0 57'0 56.7 56.7 56.4 56:4 560 560 Ο Ο The temperature decreased from 38°.5 on the ground to 36°-6 at the height of 300 feet; was then very nearly stationary to the height of 1500 feet, de creasing to 36°-1 at this elevation; it then increased to 37°.2 at the height of 1800 feet, the sky being cloudy as seen from here, and the air was misty. In the next 100 feet the temperature declined 0°.2, and as much as 1°.4 in the succeeding 100 feet; the temperature then declined slowly to 34° at 2600 feet, the clouds being at a lower elevation: the decline of temperature continued to the height of 4000 feet, where it was 2740, and there was very little change in the next 600 feet. On descending, the temperature slowly and steadily increased to 32°-4 at the height of 2500 feet, when the light was accidentally extinguished, and no more observations could be made. |